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SEC Preventive ClassesSecondary Education Certificate

Examination Papers – 2019

Physics

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The University of Malta, including the Matriculation and Secondary Education Certificate Examination Board, shall not be held responsible for any mistakes in the questions as printed or the

answers, workings or comments as contained in this publication.

Index Number:________________ SEC24/1.19m

© The MATSEC Examinations Board reserves all rights on the examination questions in all examination papers set by the said Board.

MATRICULATION AND SECONDARY EDUCATION CERTIFICATE

EXAMINATIONS BOARD

SECONDARY EDUCATION CERTIFICATE LEVEL

2019 MAIN SESSION

SUBJECT: Physics

PAPER NUMBER: I DATE: 27th April 2019 TIME: 9:00 a.m. to 11:05 a.m.

Answer ALL questions.

You are requested to show your working and to write the units where necessary.

When necessary, take g, acceleration due to gravity, as 10 m/s2.

SEC24/1.19m

DO NOT WRITE ABOVE THIS LINE

10

1. At the end of the last Apollo 15 mission, Commander David Scott performed a live

demonstration on the Moon. He dropped a hammer and a feather from the same height, and

these touched the ground at the same time. One reason for this is the lack of air resistance.

a. The graph shows how the velocity of the feather changed over time as it fell on the Moon.

i. Use the graph to find the acceleration due to gravity on the Moon.

(2)

ii. The mass of the feather is 30 g. Calculate the downward force acting on it.

(2)

iii. Calculate the height from which the feather was dropped.

(2)

b. The experiment was repeated on Earth, and this time the hammer reached the ground

before the feather because of the presence of air resistance.

i. The acceleration due to gravity on Earth is much larger than that on the Moon. Give

ONE reason for this.

(1)

ii. At a particular point, the force of air-resistance acting on the falling feather is 0.27 N.

Calculate the acceleration of the feather at that point.

(3)

(Total: 10 marks)

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2. Isaac and Anna have been asked by their teacher to carryout an experiment to verify Hooke's Law.

a. They set up the apparatus as shown in the diagram.i. State Hooke's Law.

(2)

ii. When they start the experiment, Isaac finds it difficult to take measurements accurately

from the ruler with the apparatus given and suggests adding an extra piece of

apparatus. What other apparatus do they need?

(1) iii. Draw this other piece of apparatus mentioned in part (ii) on the diagram above. (1)

iv. State ONE precaution they should take to ensure accurate results.

(1)

v. They noted the initial length of the spring without any mass loaded to it. Each time a

new mass was added, the new length of the spring was recorded. In the spaces (i) and

(ii) below, fill in the headings of the TW0 other quantities required for this investigation.

Include BOTH quantities and units.

Mass/kg (i) New length of

spring/m

(ii)

(2)

b. They noted that the length of the spring without any mass loaded to it was 5.0 cm. With a

mass of 0.2 , ’ w length is 12.5 . H ’ w

obeyed, calculate the new length of the spring when a mass of 0.5 kg is used.

(3)

(Total: 10 marks)

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10

3. The figure shows a microwave oven connected to the mains supply by a three-pin plug.

a. The diagram below shows the inner wiring of a three-pin plug. Label the FOUR parts

indicated. (4)

b. The microwave oven has a power input of 1270 W when used with a 230 V supply.

i. Calculate the current flowing through the microwave oven.

(2)

ii. Determine the total cost when the oven is turned on for 30 minutes, given that one

kWh of electricity costs 11 c.

(3)

c. To which part of the appliance is the wire labelled as (i) in the diagram connected?

(1)

(Total: 10 marks)

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4. a. A syringe containing air at room temperature is connected to a

pressure gauge, which is an instrument that shows the

pressure of liquids and gases.

i. Explain how the air particles inside the syringe create a

pressure on its walls.

(1)

ii. The plunger is then pulled outward, to increase the volume of air. State what

happens to the reading on the pressure gauge, and explain your answer, in terms of

the behaviour of the air particles.

(2)

iii. The plunger is now locked in position, to keep a

constant volume. The syringe is placed in a

container of hot water. State what happens to the

pressure of air inside the syringe, and explain your

answer, in terms of the behaviour of the air

particles.

(2)

b. The Earth is surrounded by a layer of air. The table below shows how the value of

w ’ .

Height/km 0 5 10 15 20 25

Pressure/ kPa 101 54 27 12 5.5 2.5

i. State the value of atmospheric pressure, in Pa, at a height of 5 km. __________ (1)

ii. State what happens to the atmospheric pressure with increase in height above the

surface. Give ONE reason why this happens.

(2)

iii. Aircrafts normally fly at a height of about 10 km. The inside of the aircraft is kept at

atmospheric pressure. Explain why the doors and windows of the aircraft need to be

air tight.

(2)

(Total: 10 marks)

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5. An experiment to measure the speed of sound in air was carried out in an open field.

As the bell rings, the sound is received by the two wireless microphones placed at a

measured distance, d, apart. The timer records the time taken by the sound wave to travel

from microphone 1 to microphone 2.

a. What type of wave is a sound wave? (1)

b. Explain how these waves travel through air.

(1)

c. The following set of data was recorded.

Measured

distance d/m 15 25 35 45 55 65

Time t/s 0.05 0.08 0.11 0.14 0.17 0.20

i. Plot a graph of measured distance d/m (y-axis) against time t/s (x-axis). (4)

ii. Use your graph to calculate the speed of sound in air.

(2)

iii. The experiment is repeated under water, where the microphones can still detect the

sound of the bell. State and explain any changes in the time of travel of the wave.

(2)

(Total: 10 marks)

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6. The radioactive isotope Technetium-99 is used in stress tests to

monitor blood flow. Technetium-99 emits gamma rays and its half-

life is six hours.

(https://bit.ly/2M7Nnk8)

a. What is meant by the term isotope?

(2)

b. The symbol for Technetium-99 is TC. Give the value of the:

i. proton number;

(1)

ii. neutron number;

(1)

iii. electron number.

(1)

c. State ONE property of gamma radiation.

(1)

d. Name ONE other practical use of gamma radiation.

(1)

e. Why is it necessary to use an isotope with a short half-life in this case?

(1)

f. If 2 g of Technetium-99 is injected into a patient, what would be the mass of the remaining

radioactive sample after 18 hours?

(2)

(Total: 10 marks)

9943

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7. a. A mineral water plastic bottle contains 2.0 x 10-3 m3 of water and has a total mass

of 2.04 kg.

i. Calculate the mass, in kg, of the water in the bottle given that the density of

water is 1000 kg/m3.

(2)

ii. Hence, calculate the mass, in kg, of the empty plastic bottle.

(1)

iii. If around 50 million of these water bottles were to be collected for recycling every

year, calculate the volume, in m3, of plastic collected yearly. Take the density of

plastic used to be 1380 kg/m3.

(2)

iv. Empty plastic bottles collected in bulk for recycling are usually compressed using a

hydraulic press so that it takes up less space. What effect does this have on the

density of the waste collected?

(1)

b. Underline ONE correct answer for the given situation.

Lisa puts some ice cubes in a glass of water and notices that ice floats. This happens

because the spacing of the particles in ice is:

smaller than that in water;

larger than that in water;

at the same distance as that in water. (1)

c. Some water is poured into a glass, and it is left exposed directly to the Sun. After a few

hours, the level of the water is considerably reduced. Explain why and how this

happens.

(3)

(Total: 10 marks)

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8. The electrical water heater shown in the diagram contains 80 kg

of water. Cold water at 20 oC enters from tube A and is heated

by the heating element. The hot water produced leaves the

heater from tube B.

a. Show in the diagram below, the energy changes occurring in the heating element. (1)

b. Hot water flows from the bottom to the top inside the tank. What is this process called?

(1)

c. Calculate the energy required to heat the water in the tank to 60 oC, given that the specific

heat capacity of water is 4200 J/kgoC.

(2)

d. Calculate the time taken to heat the water, given that the power of the heater is 1500 W.

(2)

e. e. In practice, the time required is longer than the amount calculated in part (d) as not all the heat produced by the heating element is absorbed by the water. Give TWO reasons for this, stating clearly where the 'lost' energy is being transferred to.

i. (1)

ii. (1)

f. A solar water heater could also be used to heat water in our households.

i. State ONE advantage of using this method.

(1)

ii. Why are some surfaces of a solar water heater painted black?

(1)

(Total: 10 marks)

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10

9. The Earth is one of the planets in our solar system.

a. i. Why do we refer to it as the solar system?

(1)

ii. State the name of a dwarf planet in our solar system.

(1)

iii. This dwarf planet is around 0.000624 light years away from the Earth. Explain the

meaning of the term light year.

(1)

b. The following table shows the average distances of the Earth and Mars from the Sun, and

the force of gravity acting on each kilogram placed at their surface.

i. Which of the two planets has the longest year? Explain.

(2)

ii. On which of the two planets would you experience a larger weight? Explain.

c.

(1)

d. Scientists have recently sent a spacecraft, named InSight, to Mars. It will send useful

information about the planet using radio signals. Calculate how long radio waves travelling

at 3 x 108 m/s would take to reach us from Mars, if the average distance between Earth

and Mars is 2.25 x 1011 m.

(2)

(Total: 10 marks)

Page 11 of 12

Average distance from Sun

(million km)

Force of gravity acting on each kilogram

(N/kg)

Earth 150 10.0

Mars 230 3.7

Mars' axis of rotation is tilted, just like Earth's. What does this tilt cause on these planets?

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10.

a. Tower cranes such as the one shown in the diagram are common

at construction sites. These are used to lift and carry heavy

loads, using the principle of moments to keep in equilibrium.

State this principle.

(2)

b. The setup shown is used to investigate the principle of moments. A uniform metre ruler is

hung from a pivot and is supported by a Newton meter that produces an upward force, F.

When a weight, W is hung in the position shown, the ruler is perfectly horizontal.

i. Include an arrow in the setup to show the weight of the ruler. Label this as R. (1)

ii. The mass of the ruler used is 0.12 kg. Calculate the moment produced by the

weight of the ruler, if it acts at 0.35 m from the pivot. Give your answer in Nm.

(2)

iii. The value of W is 2.0 N and its distance from the pivot is 0.75 m. Use the principle of

moments, to calculate the upward force F, produced by the Newton meter to keep the

ruler horizontal. The distance between the Newton meter and the pivot is 0.50 m.

(4)

c. If the weight, W is moved closer to the pivot, would the Newton meter have to produce a

larger or smaller force F, to keep the ruler horizontal?

(1)

(Total: 10 marks)

Index Number:________________ SEC24/2A.19m



EXAMINATIONS BOARD


2019 MAIN SESSION

SUBJECT: Physics

PAPER NUMBER: IIA DATE: 27th April 2019 TIME: 4:00 p.m. to 6:05 p.m.



When necessary, take g, acceleration due to gravity, as 10m/s2.

SEC24/2A.19m


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20

1. The following diagram shows a marksman on top of a building, firing a bullet horizontally

towards a wooden target of mass 100 g. This target was thrown upward from a launching

device placed at ground level.

a. The launching device threw the wooden target to a vertical height of 9 m. Ignore the effects

of air-resistance.

i. On the diagram below, draw and label the TWO forces acting on the wooden target at

the instant it is being thrown upwards by the device. (2)

ii. State the value of the acceleration due to gravity acting on the wooden target as it

moves upwards.

(1)

iii. Calculate the resultant force acting on the wooden target as it is moves upwards.

(2)

iv. What is the velocity of the wooden target at the top of its motion? (1)

v. Calculate the velocity with which the wooden target was launched.

(2)

vi. Find the time taken for the target to reach this maximum height.

(2)

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b. In practice, air resistance acts on the wooden target as it moves upwards.

State how air-resistance will affect the deceleration and the maximum height reached by

the wooden target.

Deceleration (1)

Maximum height (1)

c. Just as the wooden target reaches its maximum height, a bullet of mass 42 g, hits it with a

speed of 300 m/s.

i. Calculate the momentum of the bullet before it hits the wooden target.

(2)

ii. The bullet becomes embedded in the wooden target. Calculate the combined velocity of

the bullet and wooden target after the collision.

(2)

d. As the marksman fires the bullet, the rifle recoils backwards and hits his shoulder.

i. Explain why the rifle recoils backwards, naming a law used to support your answer.

(2)

ii. A shoulder protection pad with a layer of foam inside is worn by the marksman. Explain

how this affects the force of impact on the shoulder.

(2)

(Total:20 marks)

https://www.alibaba.com

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2.

a. The table below shows different telescopes used to detect radiations from different sources.

All these radiations travel at 3 x 108 m/s.

i. Name TWO other properties common to the radiations detected.

(2)

ii. Mention TWO other electromagnetic radiations whose wavelengths are smaller than the

radiations captured by the telescopes mentioned above.

(2)

iii. Calculate the frequency of the infrared waves detected by the Mauna Kea Observatory.

(2)

iv. State a use of each of the radiations listed below.

Infrared: (1)

Radio waves: (1)

b. The diagram shows part of a telescope. Light

from a distant object is captured by a lens and

focused at a point f, as shown.

i. What type of lens is used in this telescope? (1)

ii. When parallel rays pass through the lens, they and meet at the focal point, f. (1)

Telescope Type of radiation detected Wavelength detected

Mauna Kea Observatory

(Hawaii) Infrared 25 x 10-6 m

Mount Graham (Arizona) Visible light 600 x 10-9 m

Effelsberg Observatory

(Bonn, Germany) Radio Waves 0.21 m

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iii. The ’ 0 . Describe briefly how a student can

do a rough verification of the focal length of a lens.

(3)

c. The student wants to use the same lens as a magnifying glass, to be able to read some small

text.

i. Suggest a distance, at which the lens should be placed away from

the text for this to happen.

(1)

ii. An object whose actual height is 1.5 cm, appears to be enlarged when viewed through

the lens. If the magnification of the lens is 4, find the height of the image.

(2)

iii. In the space below, draw a ray diagram to show how the lens produces an image when

used as a magnifying glass. Label the object O and the image I. (2)

iv. The image produced is enlarged. Mention TWO other characteristics of the image

formed.

(2)

(Total: 20 marks)

(https://www.amazon.com)

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20

3. This question is about energy transfer.

a. Lisa is going out on a picnic and she prepares a hot drink in a vacuum flask, designed to

keep liquid warm for some time. The diagram below shows the inside of such a flask.

(https://www.123rf.com)

State which method of heat transfer is being reduced by the parts of the flask listed below:

i. glass bulb; (1)

ii. silvered surface; (1)

iii. plastic stopper; (1)

iv. vacuum between walls. and (2)

b. During the Physics lesson Lisa is told that there are also vacuum flasks with an inside bulb

made of stainless steel, instead of glass. She wants to carry out an experiment to

investigate which of the two flasks keeps liquids warm for a longer time. She is provided

with a stainless steel flask and a glass flask of the same size, two thermometers, a

stopwatch and hot water.

i. Describe how she should carry out the experiment.

(4)

Page 6 of 12

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20

ii. State TWO important precautions necessary in this experiment.

(2)

iii. The table below contains the three columns used to record the readings taken. Fill in

the other TWO column headings, with the quantities measured and their units. (2)

Time/s

iv. Label the y-axis of this graph and draw a rough sketch of the TWO graphs expected

for the two materials. You are not expected to identify which graph is for glass and

which for stainless steel. (3)

v. Why is it better to plot the two graphs on the same axes and not on separate ones?

(1)

vi. How can Lisa use her graphs to decide which flask is better at keeping hot liquids

warm for a longer time?

(1)

c. Vacuum flasks are also used to keep certain liquids at very low temperatures. In industry,

they can be used to keep liquid air at -200 oC. Explain, in terms of heat transfer, how a

flask can keep cold liquids at low temperatures.

(2)

(Total:20 marks)

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4.

a. Michael wants to investigate the relationship between the thickness of copper wires and the

current at which they melt. This indicates their fuse rating, if they had to be used as a fuse

in a circuit. The following apparatus has been provided from the school laboratory:

Connecting wires

Switch

Battery

Ammeter

Variable resistor

Copper wires, of given different thickness and same length, used as a fuse.

i. Draw the circuit required to measure at which current the copper wires would melt. (3)

ii. Write a brief description of how they will use the circuit in part (a)(i) to check the

relationship between the thickness of the wire and the approximate value of the current

needed to melt the wire.

(4)

iii. State ONE precaution needed when conducting the experiment.

(1)

iv. Predict the relationship between the thickness of the wires and the current they can

withstand before melting.

(1)

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20

b. The fuse shown in the figure below allows a current of 3 A to flow before melting. The fuse

is connected to a w w 4 Ω Ω.

i. Will the fuse melt? Show your working.

(3)

ii. The two resistors are now connected in parallel. Will the fuse melt? Show your working.

(3)

c. Which THREE other factors apart from the thickness of the wire, can affect the value of its

resistance?

(3)

d. Mention TWO safety measures used at home to prevent electric shocks.

(2)

(Total: 20 marks)

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5.

a. Describe how a steel bar can be made into a permanent magnet using the electrical

method.

(3)

b. Draw the magnetic field pattern around the permanent bar magnet produced in the

previous question. Show clearly the poles of the magnet. (3)

c. Give ONE method used to demagnetise the steel bar.

(1)

d. Kimberley wants to produce a model of a magnetic relay switch to light the bulb in circuit B.

The circuit she sets up is shown below:

i. What happens to the iron core as current flows in circuit A?

(1)

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20

ii. When circuit A was switched on the first time, Kimberley noticed that the iron bar did not

move, and the light bulb in circuit B did not switch on. List TWO changes she can make

to circuit A, to make the iron bar move towards the iron core. State the effect of these

changes.

(3)

iii. After the necessary changes are done, circuit A is switched on again, and the bulb in

circuit B lights up. Explain how this happens.

(4)

iv. Kimberley now modifies circuit B as shown below. Explain what happens when circuit A is

switched on.

(3)

v. Explain how the above set-up could be used as a safety device of our homes.

(2)

(Total: 20 marks)

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Blank Page

Index Number:________________ SEC24/2B.19m



EXAMINATIONS BOARD


2019 MAIN SESSION

SUBJECT: Physics

PAPER NUMBER: IIB DATE: 27th April 2019 TIME: 4:00 p.m. to 6:05 p.m.




SEC24/2B.19m


20

1.

The following diagram shows a marksman on top of a building, firing a bullet horizontally

towards a wooden target. This target was thrown upward from a launching device placed

at ground level.

a. The wooden target reaches a maximum height of 9 m, before it starts falling again. Ignore

the effects of air-resistance.

i. Label F1 and F2, the forces acting on the wooden target at the instant it is being thrown

upwards by the device. (2)

ii. State the value of the acceleration due to gravity acting on the wooden target as it moves

upwards.

(1)

iii. The mass of the wooden target is 0.1 kg. Calculate the resultant force acting on the

wooden target.

(2)

iv. What is the velocity of the wooden target at the top of its motion? (1)

v. Calculate the initial velocity with which the wooden target was launched.

(2)

vi. Find the time taken for the target to reach the maximum height.

(2)

Page 2 of 12

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20

b. Just as the wooden target reaches its maximum height, a bullet of mass 0.042 kg, hits it

with a speed of 300 m/s.

i. Calculate the momentum of the bullet before it hits the wooden target.

(2)

ii. The law of conservation of momentum states that the total momentum ____________

provided that

(2)

iii. The bullet gets stuck into the wooden target. Calculate their total mass.

(1)

iv. Calculate the velocity of the wooden target and bullet after they stick together.

(2)

c. As the marksman fires the bullet, the rifle recoils backwards and hits his shoulder.

i. A law that explains why the rifle recoils backwards is w ’ rd law of Motion, which

states that:

(1)

ii. A shoulder protection pad with a layer of foam inside is worn

by the marksman. Explain how this reduces the force of

impact on the shoulder.

(2)

(Total: 20 marks)

https://www.alibaba.com

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2.

a. The table below shows different telescopes used to detect radiations from different sources.

i. Name TWO common properties of the radiations detected.

(2)

ii. Calculate the frequency of the infrared waves detected by the Mauna Kea Observatory if

these waves travel at 3 x 108 m/s.

(3)

iii. List TWO other electromagnetic radiations apart from those mentioned above.

(2)

b. The diagram shows part of a telescope. Light

from a distant object is captured by the lens

and focused at point f, as shown.

Underline ONE correct word from inside the brackets, for each of the below sentences.

The lens used is a (concave / convex) lens. (1)

When parallel rays pass through the lens, they (converge / diverge / diffract) and meet at

the focal point, f. (1)

Telescope Type of radiation detected Wavelength detected

Mauna Kea

Observatory (Hawaii) Infrared 25 x 10-6 m

Mount Graham

(Arizona) Visible light 600 x 10-9 m

Effelsberg Observatory

(Bonn Germany) Radio Waves 0.21 m

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20

c.

i. What do you understand by focal length of 12 cm?

(1)

ii. Put the following statements in order by using the number 1, 2 and 3 to explain how the

student can do a rough measurement of the focal length of the lens. (3)

Move the lens towards and away from the screen until a sharp image of

the distant object is obtained on the screen.

Position the lens between a distant bright source of light and a screen.

Measure the distance between the lens and the screen.

d. The student wants to use the same lens as a magnifying glass, to be able

to read some small text.

i. A picture whose actual height is 1.5 cm, is seen as an image with a

height of 6 cm. Calculate the magnification of the lens.

(2)

ii. The diagram below shows a vertical line representing the lens, and an upright arrow

showing an object, O. Complete the ray diagram to show how the lens produces an

image when used as a magnifying glass. Label the image I. (3)

iii. The image produced is virtual. Mention TWO other characteristics of the image

formed.

(2)

(Total: 20 marks)

(https://www.amazon.com)

The telescope's lins has a focal length of 12 cm

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3.

a. Lisa is going out on a picnic and she prepares a hot drink in a vacuum flask, designed to

keep liquid warm for some time. The diagram below shows the inside of such a flask.

(https://www.123rf.com)

State which of conduction, convection and radiation, is being reduced by the parts of the flask listed

below, to help keep the liquid warm. Each mode of heat transfer can be listed more than once.

i. glass bulb; (1)

ii. silvered wall; (1)

iii. plastic stopper; (1)

iv. vacuum between the walls. and (2)

b. During the Physics lesson, Lisa is told that there are also vacuum flasks with an inside bulb

made of stainless steel, instead of glass. She wants to carry out an experiment to

investigate which of the two flasks keeps liquids warm for a longer time. She is provided

with a stainless steel flask and a glass flask of the same size, two thermometers, a

stopwatch and hot water.

i. Describe how she should carry out the experiment, by numbering the following

statements in order from one to four. (4)

Switch on the stopwatch and take the temperature of water at regular intervals.

Repeat the same method, using the second flask containing the same volume of

water, at the same initial temperature.

Read the initial temperature of the water, using a thermometer.

Fill the first flask with a known volume of hot water.

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20

ii. State TWO important necessary precautions, other than the ones listed in the

method.

(2)

iii. The table below contains three columns used to record the readings taken. Fill in the

heading of the first and third column, with the quantities measured and their units.

(3)

Temperature of water

in the glass flask (oC)

iv. The graphs plotted are shown below. Label the TWO axes of this graph. (2)

v. Why is it better to plot the two graphs on the same axes and not on separate ones?

(1)

vi. Mark with an X the curve for the flask that keeps the liquid warm for a longer time.

(1)

c. Vacuum flasks are also used to keep certain liquids at very low temperatures. Explain, in

terms of heat transfer, how flasks can keep cold liquids at low temperatures.

(2)

(Total: 20 marks)

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4.

a. Michael wants to investigate the relationship between the thickness of copper wires and the

current at which they melt.

i. The following circuit has been set up as shown below. Label the FOUR components

indicated. (4)

ii. Use the words below to complete the method used for this investigation. Each word can

be used only once.

decreased current melted wire variable resistor

The apparatus was set up as shown above. The first was

attached to the crocodile clips. The circuit was switched on and the

was set to maximum resistance as to have the least

flowing. The resistance was

gradually until the copper wire melted. The current reading was taken just before the

wire . This procedure was repeated each time by varying the

thickness of the copper wire. (5)

iii. Predict the relationship between the thickness of the wires and the current they can

withstand before melting.

(1)

b. The fuse shown in the figure allows 3 A of current to flow before melting. The fuse is

connected to a 12 V battery and in series with two resistors of 4 Ω Ω.

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i. What is the total resistance of the circuit?

(1)

ii. What is the current flowing through the circuit?

(2)

iii. Will the fuse melt at this current?

(1)

iv. If the two resistors are now connected in parallel as shown. Calculate the total

resistance of the circuit.

(2)

v. Calculate the total current flowing in the parallel circuit.

(2)

vi. Will the fuse melt in this case?

(1)

c. Mention ONE other safety measure used at home to prevent electric shocks.

(1)

(Total: 20 marks)

SEC24/2B.19m


Page 10 of 12

20

5.

a. Underline the correct word from the ones in brackets, to complete the method used to create

a permanent magnet.

A wire is wrapped around a (steel / iron) bar. (Alternating / Direct) current is passed

through the wire. The circuit is switched off and the wire is unwrapped leaving a permanent

magnet. (2)

b. Draw the magnetic field pattern around the permanent bar magnet produced in the previous

question. Show clearly the poles of the magnet. (3)

c. Give ONE method used to demagnetise the bar.

(1)

d. Kimberley wants to produce a model of a magnetic relay switch, to light the bulb in circuit

B. The circuit she sets up is shown below:

SEC24/2B.19m


20

i. What will happen to the iron core as soon as the switch in circuit A is closed?

(2)

ii. Use numbers one to five, to rearrange the following list in order and obtain the correct

sequence of events as circuit A is switched on. (5)

Current flows around the iron core.

The iron bar is attracted towards the temporary magnet.

The switch in circuit A is switched on.

The contact points make contact.

A complete circuit is now formed in circuit B, and the bulb lights up.

iii. List TWO changes Kimberley can make to circuit A, to obtain a stronger attraction

between the iron bar and the iron core.

(2)

iv. Kimberley now modifies circuit B as shown below. Explain what happens when circuit A is

switched on.

(3)

v. This set-up can be used as a circuit breaker. Explain how this is used as a safety device

in our homes.

(2)

(Total: 20 marks)

Page 11 of 12

Index Number: ______________ SEC24/1.19s



EXAMINATIONS BOARD


2019 SUPPLEMENTARY SESSION

SUBJECT: Physics

PAPER NUMBER: I DATE: 29th August 2019 TIME: 9:00 a.m. to 11:05 a.m.



When necessary, take g, acceleration due to gravity, as 10 m/s2.

SEC24/1.19s


Page 2 of 12 10

1. The diagram shows a winch being used to lift a block full of cement off the ground. The

block accelerates upwards for a brief time and then it continues to rise at a constant speed

of 15 metres per minute. The mass of the block and cement is 30 kg.

(1)

(1)

a. Name the TWO forces acting on the block.

Force 1

(2)

c. Comment on the size of these two forces during the initial brief acceleration upwards.

(1)

d. Comment on the size of these forces when the block moves at a constant speed.

(1)

e. Calculate the unbalanced force required if the initial acceleration of the block is

2.5 m/s2.

(2)

f. Calculate the upward force required to give the acceleration mentioned in part (e).

(2)

(Total: 10 marks)

Force 2

b. Calculate the constant speed of the block in m/s.

SEC24/1.19s


10

2. The only seven heavenly bodies in our solar system

visible in the sky up to the 17th century were the sun

and the moon and the planets Mercury, Venus, Mars,

Jupiter and Saturn.

a. In 1610, Galileo was looking through the

telescope, and observed four moons orbiting the

planet Jupiter. (https://blendermarket.com)

i. What force keeps these moons orbiting around Jupiter?

(1)

ii. Jupiter is the planet with the largest mass in our solar system. What effect does this

have on the force mentioned in part (i)?

(1)

iii. On what other factor, apart from mass, does this force depend?

(1)

iv. Jupiter has the largest number of known moons, 79, amongst the planets in our solar

system. Why is this so?

(1)

v. Which are the other TWO planets in our solar system apart from Earth and the ones

mentioned above?

(2)

vi. Why are these two planets not normally visible with the naked eye?

(1)

b. Up to about 50 years ago, images of the planets and other heavenly bodies could only be

taken by telescopes based on earth, known as terrestrial telescopes. In the meantime,

telescopes have been fitted to satellites orbiting the earth. These are known as space

telescopes and can take exceptionally clear images of heavenly bodies.

i. Explain why space telescopes give clearer images than terrestrial ones.

(1)

ii. How are the images taken by space telescopes sent to earth?

(1)

iii. Why are photovoltaic (solar) cells used on satellites to provide power to the electrical

and electronic equipment on board?

(1)

(Total: 10 marks)

Page 3 of 12

SEC24/1.19s


10

3. Dancers often stand in front of mirrors so that they can see their moves as they practice.

The diagram shows a dancer in front of the mirror.

a. Draw a ray to show how the dancer can see her right foot through the mirror. Include

the path of the ray and the normal. (3)

b. Mark with a cross (x) the position of the ’ . (1)

c. The dancer notices that when she lifts her right foot, the image lifts the left foot. This is

because the image is . (1)

d. Mention TWO other properties of the image observed in the mirror.

(2)

e. The coach observes four dancers, A,B,C and D, through the glass pane on the door of

the dance studio.

(1) i. Which dancer cannot be seen by the coach?

ii. Explain why this dancer cannot be seen by the coach.

(2)

(Total: 10 marks)

Page 4 of 12

SEC24/1.19s


Page 5 of 12 10

4. The figure below shows particles on the surface of water. A wave moves from left to right.

a. Explain the movement of each particle if the wave is a transverse wave.

(2)

b. On the graph below draw a transverse wave that has amplitude of 20 mm and a

wavelength of 60 cm. (2)

c. The wave has a periodic time of 4 x 10 -4 s.

i. Find the frequency of the water wave.

(2)

ii. Calculate the speed of this wave.

(2)

d. The water wave enters a shallower region. Mention TWO changes that happen to the

water wave as it enters the shallower part.

(2)

(Total: 10 marks)

SEC24/1.19s


Page 6 of 12 10

5. William is investigating how the strength of a solenoid with an iron core varies with current.

a. What component must be added to the circuit to:

i. vary the current?

(1)

ii. measure the current?

(1)

b. Apparatus X in the above diagram is used to measure the force. State its name.

(1)

William varies the current, each time measuring the force produced. The table with the results

obtained is displayed below.

Force F / N 0 1.0 2.0 3.0 4.0

Current I / A 0 0.5 1.0 1.5 2.0

c. Plot a graph of the force F (y-axis) against current I (x-axis). (4)

d. From the graph it can be concluded that the Force and Current are:

(1)

e. Use your graph to find the value of current that produces a force of 1.8 N.

(1)

f. Apart from varying the current what changes could be made to the solenoid to provide a

stronger attractive force?

(1)

(Total: 10 marks)

SEC24/1.19s


Page 7 of 12 10

SEC24/1.19s


Page 8 of 12 10

6. When a well is dry, a stone dropped from rest at the top takes 4 s to hit the bottom.

a. With what speed will the stone touch the bottom of the well?

(2)

b. How deep is the well?

(2)

c. A person at the top can tell when the stone hits the bottom by the sound it makes on

impact. Calculate how long sound takes to reach the person on top, if sound travels at

320 m/s in air.

(2)

d. Explain, using air particles, how sound waves travel from the bottom of the well towards

the person on top. Include the name of this type of wave.

(2)

e. When the well is full of water, audible sound is not used to find its depth. Instead an

ultrasound pulse is sent from a sonar machine placed at the top.

i. What is ultra sound?

(1)

ii. Underline the correct statement.

Ultra sound is preferred over normal sound since it:

can pass through water but it is reflected by stone.

is refracted by water and absorbed by stone.

is diffracted by water and refracted by stone. (1)

(Total: 10 marks)

SEC24/1.19s


Page 9 of 12 10

7. A swimming pool is lit by a lamp at the bottom of the pool, 1.2 m deep. The directions of

three rays of light from the lamp are shown.

a. Explain why ray A does not bend as it exits the water and travels in air.

(1)

b. State ONE change that occurs to the light wave as it exits the water.

(1)

c. Continue the path of ray B in air. (2)

d. Ray C goes through total internal reflection.

i. Give ONE condition necessary for this phenomenon to take place.

(1)

ii. What is the name given to angle x and angle y above?

(1) Angle x

Angle y (1)

iii. What can you say about angle x and angle y? (1)

e. When a boy looks down at the lamp, he estimates it to be 90 cm below the surface of

the water. Calculate the refractive index of water.

(2)

(Total: 10 marks)

SEC24/1.19s


Page 10 of 12 10

8. The velocity- ’ on a Sunday morning.

a. C ’ .

(2)

b. For how long did Emma travel at a constant speed? Give your answer in seconds.

(1)

c. i. State between which minutes ’ w .

(1)

ii. Hence, calculate the distance covered by Emma in this period.

(2)

d. After 3 minutes, Emma presses the brake pedal and slowly comes to rest. The

motorbike decelerates at 1 m/s2.

i. Calculate the time it took Emma to come to rest.

(2)

ii. Represent this deceleration on the graph above. (2)

(Total: 10 marks)

SEC24/1.19s


Page 11 of 12 10

9. Photographers use a light sensor to check the light conditions when taking a photograph.

The circuit above shows how the light sensor is connected. The light sensor is a special type of

resistor called L.D.R.

a. Draw the L.D.R. in the space provided between X and Y in the above circuit. (1)

b. What does L.D.R. stand for? (1)

c. Suggest another suitable use for the L.D.R.

(1)

d. Why is a milliammeter rather than an ammeter used in the circuit?

(1)

The switch is open and the milliammeter reads 0 mA when in the dark. While when there is a

bright light the milliammeter reads 4 mA.

e. How does the resistance of the sensor change as it gets darker? Explain how you arrived

at your conclusion.

(2)

f. The switch is now closed.

i. Explain why the milliammeter will now give a reading of current even when in the

dark.

(1)

ii. The milliammeter reads 5 mA. Convert 5 mA to Amps.

(1)

iii. Calculate the resistance of the fixed resistor.

(2)

(Total: 10 marks)

SEC24/1.19s


Page 12 of 12 10

10. The diagram shows a weighing scales operating on the principle of the spring balance. The

two springs hang from a fixed casing and their lower ends are attached to a crossbar. As

weights are added to the pan, the springs extend, and the toothed rack moves down. This

causes the pinion (a round wheel with toothed gears) to rotate and the pointer moves along

the dial or scale. The scale is calibrated in Newtons and has a full-scale deflection of 100 N.

a. In which direction does the pointer move when

weights are added to the pan?

(1)

b. What is the maximum mass that can be placed

on the pan to get full scale deflection?

(2)

c. Calculate the force in each spring at full scale

deflection.

(1)

d. This instrument is taken to different places on earth. It gives different readings when

loaded with the same mass. It would also give different readings on other planets which

have a different pull of gravity. In the following table mark with a whether the reading

would be 0, less than or greater than the reading obtained on the surface of the earth.

The pull of gravity of the two named planets is stated in brackets for each planet. (3)

0 less than greater than

on top of a high mountain on earth

on the surface of Jupiter (25 N/kg)

on the surface of Mercury (3.7 N/kg)

e. If the instrument had to have four similar springs instead of two, what load would give

full scale deflection of the instrument? Explain.

(2)

f. What is the advantage of having the pointer attached to this toothed gear system as

shown?

(1)

(Total: 10 marks)

Index Number: ______________ SEC24/2B.19s



EXAMINATIONS BOARD


2019 SUPPLEMENTARY SESSION

SUBJECT: Physics

PAPER NUMBER: IIB DATE: 29th August 2019 TIME: 4:00 p.m. to 6:05 p.m.




SEC24/2B.19s DO NOT WRITE ABOVE THIS LINE

Page 2 of 12

1. This question is about braking distances.

Martha and Matthew would like to investigate how different surfaces affect the braking

distance of a toy car. They set up a ramp as shown in the diagram below.

They decide to test four different surfaces: turf, gravel, polished tiles and concrete.

a. Use numbers 1 to 5 to obtain the method in the correct sequence.

This distance is labelled as braking distance and recorded in a table.

The above steps are repeated for all the other test surfaces.

The toy car is released from the top of the ramp and allowed to come to

rest.

The first test surface is placed next to the ramp.

The distance between point A and the place where the car stops is

measured.

(5)

b. Mention TWO important precautions that must be taken by Matthew and Martha to

ensure that their test is fair.

(2)

c. i. Which surface would give the longest braking distance? Underline.

Turf Gravel Polished tiles Concrete

(1)

ii. Give a reason for your choice.

(2)


Page 3 of 12

d. Martha attached a data logger at point A to record the velocity with which the car enters

the test surface.

i. During one trial, the data logger gave a velocity of 0.5 m/s at point A. If the braking

distance of the car was 0.05 m, calculate the deceleration of the car.

(2)

ii. What was the braking time during this trial?

(2)

iii. Martha made the ramp steeper such that the car passed through point A with a larger

velocity. How will this affect the braking distance of the car?

(1)

e. In practice, the stopping distance of a car does not consist only of the braking distance.

i. What name is given to the distance that the car travels before the driver puts his foot

on the brake pedal? (1)

ii. Mention ONE factor that could increase the distance the car travels in this time.

(1)

iii. The braking distance for a car travelling at normal speeds is 22 m. If the total

stopping distance of the car is 30 m, calculate how far the car travelled before the

driver put his foot on the brake.

(1)

iv. If the driver took 0.4 s before he put his foot on the brake pedal, calculate the initial

speed of the car before the braking.

(2)

(Total: 20 marks)


Page 4 of 12

2. This question is about pressure.

a. A footballer of mass 70 kg is wearing a pair of ordinary shoes. The total area of both

shoes in contact with the ground is 0.04 m2.

i. Define pressure.

(1)

ii. Calculate the pressure he exerts on the ground when standing on both feet.

(2)

iii. This footballer then puts on a pair of football shoes, shown in

the diagram on the right. Explain in terms of pressure why the

several studs at the bottom of these shoes help to increase grip

with the playing surface.

(2)

b. A sea diver is diving at a depth of 30 m in the sea.

i. Calculate the pressure that the sea water is exerting on

him given that the density of sea water is 1025 kg/m3.

(2)

ii. If atmospheric pressure on this day is 101 kPa, calculate the total pressure on the

diver.

(1)

iii. The air bubbles released by the diver at this depth are seen to increase in volume

considerably while they are rising to the surface. Explain why this increase in volume

occurs.

(2)


Page 5 of 12

c. The diagram below shows a simplified view of

the hydraulic brake system of a car. Only one

wheel and one brake cylinder is shown for

clarity. The brake pedal is pivoted at the top

and acts as a lever. When a force is applied to

the pedal as shown, the piston in the master

cylinder is pressed inwards. The pressure

exerted on the oil in the system forces the

piston in the brake cylinder to move inwards.

This action causes the brake pad to press

against the wheel disc which in turn slows down

the car.

(adapted from https://defdriving.wordpress.com)

i. A force F of 20 N is applied to the brake pedal. Use moments to calculate the force

that this produces on the piston in the master cylinder.

(2)

ii. The area of the piston in the master cylinder is 4 x 10-5 m2. Calculate the pressure

exerted on the oil by the piston in the master cylinder.

(2)

iii. What pressure is exerted by the oil on the piston in the brake cylinder?

(1)

iv. The area of the piston in the brake cylinder is 1.0 x 10-4 m2. Calculate the force that

this piston exerts on this one brake pad.

(2)

v. Give ONE advantage of using oil instead of water as a liquid here to transmit pressure.

(1)

vi. If some air manages to find its way inside the oil in this system, what effect would

this have on the braking force as calculated in part (iv)? Explain.

(2)

(Total: 20 marks)


Page 6 of 12

3. This question is about nuclear physics.

a. The Geiger–Müller tube below is switched on. It detects a small count of approximately

25 counts per minute.

i. What is this radiation called?

(1)

ii. Name TWO possible sources causing this radiation.

(2)

b. Cobalt is placed in front of the G.M. tube. The count-rate is observed to rise.

i. Write down the number of protons, neutrons and electrons for a neutral cobalt atom.

Protons: (1)

Neutrons: (1)

Electrons: (1)

ii. Cobalt-60 β . beta-particle consist of and what is

its charge?

(2)

iii. After the beta decay Nickel-60 is formed. Nickel-60 γ

(gamma) radiation. Mention TWO w β γ .

(1)

(1)


Page 7 of 12

iv. Describe an experiment you would do in order to show that beta particles, not alpha

are present.

(4)

v. Mention ONE precaution taken when using radioactive sources.

(1)

c. Carbon-14 and Carbon-12 are two isotopes of carbon.

i. What is meant by the term isotope?

(2)

Carbon-14 is a radioactive substance with a half-life of 5600 years and every gram has a count-

rate of 44 counts per minute.

ii. Explain the term half-life.

(1)

iii. What would be the count-rate for 1 g of carbon-14 in a piece of wood that is

11,200 years old?

(2)

(Total: 20 marks)


Page 8 of 12

4. This question is about thermal physics.

a. All matter is made up of particles. The following table shows the similarities and

differences in the particle properties between solids, liquids and gases. The ones for

liquids have been filled in for you. Fill in the remaining properties for solids and gases. (6)

b. A group of students are carrying out an experiment to determine the specific heat

capacity of an aluminium block, using an electrical heater. They set up the apparatus as

shown.

i. Label on the diagram the TWO pieces of apparatus A and B. (2)

ii. They will need a stopwatch and one other measuring instrument to carry out the

experiment. Name this instrument. (1)

iii. How is the energy supplied to the block calculated from the stopwatch reading and

apparatus A?

(1)

iv. The teacher advised the students to put lagging around the block. Name a material

which can be used for this purpose. (1)

v. What is the function of the lagging around the block?

(1)

solids liquids gases

spacing between

particles

closely packed but not

in order

forces between

particles strong

motion of particles

vibrate but also move

randomly throughout

the liquid


Page 9 of 12

vi. Underline the correct answer:

Without lagging, the calculated value of specific heat capacity would be smaller

than / equal to / greater than the actual value. (1)

vii. Name ONE other precaution, not already mentioned, which is necessary to obtain an

accurate result and explain how it achieves its purpose.

(2)

c. Luca and Sarah are out camping with their families close to the seaside.

i. Sarah goes swimming and notices that when she comes out of the water, she feels a

bit cold until the water still on her body dries up. Explain why cooling occurs as a

liquid evaporates.

(2)

ii. Luca had two buckets. One of them was much wider than the other but they both

had the same volume of water in them. He observed on the following day that more

water evaporated from the wide bucket than from the narrower one. Explain why

this occurred.

(1)

iii. Sarah had learned at school the fact that if the same amount of heat energy is given by

the sun to 1 kg of sand and 1 kg of water, the sand heats up much more than the water.

What can she say from this about the values of the specific heat capacity of each?

(1)

iv. Why is it that after sunset the sea takes a longer time to cool down than the sand?

(1)

(Total: 20 marks)


Page 10 of 12

5. This question is about electromagnetism.

a. Melvin sets up the following apparatus in the laboratory to investigate the generation of

electricity.

i. Label the apparatus indicated as A, B and C. (3)

ii. He moves apparatus A towards apparatus B and observes that the pointer deflects to

the right. Explain.

(2)

iii. What happens if he moves apparatus A in the opposite direction? Explain.

(2)

iv. Suggest TWO ways how a larger deflection can be obtained.

(1)

(1)

v. Suggest a suitable application for the above set up.

(1)


Page 11 of 12

b. He then sets up the following transformer with 2400 turns in the primary coil and 240

turns in the secondary coil. The primary coil is connected to a 2300 V, 1.5 A, A.C

supply.

i. Is the transformer shown above, a step-up or a step-down transformer?

(1)

ii. What is the use of such a transformer in everyday situations?

(1)

iii. Why is the core made of iron and not steel?

(2)

iv. Determine the output voltage of this transformer.

(2)

v. Calculate the output current of this transformer.

(2)

vi. In reality, values differ slightly from the ones obtained. Why are the values

different?

(1)

vii. S ’ w .

(1)

(Total: 20 marks)


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