ahm phy 4.doc

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Name:. Index: .... Class: .. Reg. No.:

MADHRASATHUL AHMADHIYYA

FIRST TERM TEST - 2008

PHYSICS GRADE 10 /

04

Paper 4 Alternative to Practical

1 hour

Candidates answer on the Question Paper.

No Additional Materials are required.

READ THESE INSTRUCTIONS FIRST

Write your Name, Index number and Register number on all the work you hand in.

Write in dark blue or black pen.

You may use a soft pencil for any diagrams, graphs or rough working.

Do not use, paper clips, highlighters, glue or correction fluid.

Answer all questions.

Write your answers in the spaces provided on the Question Paper.

At the end of the examination, fasten all your work securely together.

The number of marks is given in brackets [ ] at the end of each question or part question.

Madhrasathul Ahmadhiyya, First Term Test 2008 Physics Paper 4 Grade 10 Page 1 of 9

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1- A metal bob attached to a length of thread is heldin a clamp as shown in figure 1.1. The bob is madeto swing by moving it one side and then releasing it.

The meter rule is used to measure thedistance l between the centre of the boband the clamp.

a) Explain how you would use the meter rule to measure the value of l when l is about 90cm. You shouldmention any additional apparatus you would use. You may draw a diagram if you wish.

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................

...............

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[1

]

b) Two cards A and B are placed just behind theswinging pendulum, as shown in figure 1.2.On each card there is a vertical line.

The time for the period of oscillation of the pendulum is 1.00s. A student is asked to determine the timefor the period using a stop watch. Unfortunately the student has not used a stop watch before. Everytime interval t, what is measured by the student, is always too long by 0.50s, no other errors occur.

i) The student measured the time t1, as the time for one oscillation. What time does the stop watchrecord?

t1=..[1

]

ii) After resetting the stop watch, the time t20 for 20 oscillations was measured. What time does thestop watch record?

t20=..[1

]

iii) Using the value for t20, calculate the time, T for one oscillation.

T=..[1

]

iv) Why is it desirable to measure the time for 20 swings in order to determine the value of T?

...............[1

]


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c) The pendulum is not moving when it reaches the line on card B. When it crosses the line on card A, itis moving with maximum speed.

Why is it a good practice to start and to stop the stop watch as the pendulum crosses the line on cardA?

...

......

[1

]

2- A converging lens is used to producea real image on a screen.Some of the apparatus is shown in figure 2.1

The object is a circular hole in a piece of card.

a) What could you do to make the image appear as bright as possible? You should say what extra

equipment you would need and how you would arrange this equipment.

...

.......

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[1

]

b) Some cross wires are placed acrossthe object hole as shown in figure 2.2

In the space below draw a sketch of the real image produced by the lens.

[1

]

c) A real image is formed on the screen. State two ways in which the image is different from the object

.

.....

[2

]


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d) Give two reasons why it is better to measure the size of the image from a position behind the screenrather than in front.

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[2

3- The apparatus shown in the diagram 3.1 wasused to show how the current I in the circuitdepended on the length L of resistance wireconnected into the circuit.

The sliding contact was moved along the wire so as to obtain a set of values for L and the

corresponding currents I. The values obtained are shown in the table.

Graph I/A against L/m is plotted below


Resistance Wire

I/A 1.02 0.80 0.67 0.49 0.39 0.30 0.23

L/m 0.200 0.255 0.305 0.400 0.520 0.680 0.885

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I. Complete the following table by determining the appropriate values from the graph

[2

II. What evidence is there from the readings to show that the resistance per unit length of thewire is constant?

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.......

[1

I. The experiment was repeated with a sliding contact which was dirty. State one way in which thedirty contact might affect the current values.

.

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[1

II. After performing the experiment, it wasdiscovered that the ammeter has a zero error.The error is illustrated in diagram 3.2

Explain how the observed current values can be corrected

..

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[1

III. The ammeter gives a full scale deflection for 1.5A. Members of your class are to do this experimentfor the first time. Why would your teacher suggest that they start by using the largest possible valuefor L (approx. 1m) rather than the smallest value (say 0.1m)

..

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[1


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4 A student makes an electro magnet by wrapping wire around an iron nail. In one experiment the lengthof wire used, makes a coil of 40 turns. The coil is connected in series circuit as shown in figure 4.1

The student uses the variable resistor to obtain six different values of current through the coil. For eachvalue of current, the strength of the electromagnet is measured by the number N of paper clips that the

nail can pick up. These trials are performed and the average number of clips picked up is determined.

The students values are given in the table 1 below.

Number of turns 40

Current/A

Number N of paper clips Average number

of paper clipsTrial 1 Trial 2 Trial 3

0.5 1 0 0 0.3

1.0 6 9 6 7.0

1.5 12 15 13 13.3

2.0 24 26 23 24.3

2.5 36 37 34 35.7

3.0 37 53 41 43.7

a) Explain why you think it was a good experimental procedure to take an average of the values obtainedfor N in three trials.

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....[1

a) Explain why you think it was a good experimental procedure to take an average of the values obtainedfor N in three trials.

....

....[1


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b) i. Complete the table below.

[2

ii. With reference to above table explain how you know that the strength of the electro magnet is notdirectly proportional to the magnitude of the current through the coil.

....

.... [1

c) Table 1 shows that for a current of 3.0A the first two values for N are 37 and 53. The number 53 is43% larger than 37. Suggest one reason why there is such a large difference between the numbers ofclips.

....

.... [1

5- The apparatus shown in the diagram 5.1 was used to determine t, the maximum uniform temperaturereached, when a liquid was heated by an electric heater. The heater is not capable of heating theliquid to its boiling point.

The current through the heater was adjusted to a particular value and the power was calculated. Theexperiment was repeated for different values of current and each time the maximum temperature t wasrecorded. The table shows the values of t and P which were obtained

t/0C 28.0 40.5 43.6 50.5 58.7

P/W 0.250 0.563 0.640 0.820 1.00

a) I. Plot the graph of t/0C against P/W on a graph sheet. Start both axes at the origin i.e. t/0C = 0and P/W= 0. Extend the line so that it crosses the t/0C [2

II. From the graph, determine the value of t when P= 0. Call this value t0.

..


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b I. Why does the temperature not rise when P=0?

. [1

II. What does the temperature, t0 represent?

[1

c) Why does the stirring help to obtain a uniform temperature?

[1

d) How would you know that the temperature was

a. Uniform..

b. Maximum...

[1

END


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ahm phy 4.doc