Reinforcement Practice 1

Reinforcement Practice 1Part A (Objective)

Choose the correct answer.

The above figure shows a micrometer screw gauge during the zero measurement. Each reading that is obtained with the micrometer screw gauge must be corrected by

Aadding 0.04 mm

Bsubtracting 0.04 mm

C adding 0.40 mm

Dsubtracting 0.40 mm

1 An ammeter cannot provide a very accurate reading. Which of the following is one of the reasons for this?

AThe ammeters smallest measurement unit is too bigBThe ammeter has a large full scale deviation

CThe ammeter cannot be calibrated accurately

DThe ammeter changes the current value that is being measured

The above figure shows a ruler that is used to measure the size of an object. The length of the object isA1.4 cm

B1.9 cm

C2.0 cm

D2.3 cm

2 Which of the following physical quantities is a derived quantity?ALength

BTemperature

CForce

DMass

The above figure shows the reading displayed by a vernier calliper when it is used to measure the size of an object. What is the size of the object if the zero error of the calliper is 0.03 cm?

A2.10 cm

B2.13 cm

C2.16 cm

D2.19 cm 3 An oscilloscope records a time interval of 25 ns. What is the time period in the unit s?A2.5 x 10-5 s

B2.5 x 10-6 s

C2.5 x 10-7 s

D2.5 x 10-8 s

4 A suitable graph scale must be shown effectively. Choose the scale that can be managed easily.

A1 cm to 3 units

B2 cm to 10 units

C3 cm to 5 units

D4 cm to 7 units

5 Which of the following force-compression graphs shows that the compression of a spring is directly proportional with the force that is applied?A

B

C

D

The above table shows the data of an experiment. Which of the following statements is true about the experiment?

AThe variable that is not dependant on the experiment is the temperature

BThe variable that is dependant on the experiment is the time

CTemperature changes inversely to time

DThe absolute error of the thermometer used is 0.5C

6 Which of the following statements is true about measurement?AThe accuracy of time measurement by a stopwatch depends on the type of watch

BThe unit of measurement of a thermometer is Kelvin

CAn ammeter is more sensitive than a miliammeter

DThe metre ruler has an accuracy of 0.1 cm

7 Which of the following statements is not true about the physical quantity?AA physical quantity comprises the basic quantity and the derived quantity

BDerived quantity is defined in the mentioning of the basic quantity

CThe quantity of length is measured with the metre unit

DAn example of the basic quantity is velocity

8 The sensitivity of the mercury thermometer is influenced by the following exceptAthe thickness of the bulb wallBthe length of the thermometer

Cthe colour of the mercury

Dthe size of the bulb

The above figure shows the graph of potential difference against the current. Which of the following statements is not true?AThe gradient of the graph has a positive value

BThe value of the potential difference is approximately 1.5 V when the current is zero

CThe value of the potential difference decreases uniformly according to the current

DThe apparatus for measuring the potential difference is the voltmeter

9 Which of the following statements is true about accuracy and sensitivity?AAccuracy is the difference between the measured value and the zero error value

BSensitivity is the ability of the measuring apparatus to detect the error of the quantity that is measuredCAccuracy can be shown by the number of repeated measurement readings

DThe measuring apparatus that is sensitive will always give an accurate measurement

10 Which of the following SI prefixes is correct?A1 MW = 106 W

B1 mA = 10-2 A

C1 s = 10-9 s

D1 mF = 106 F

Part B (Subjective)

Answer the following questions.1 (a) The following table shows five basic quantities in the SI unit. Complete the table.

Basic quantityBasic unit

NameSymbolNameSymbol

lengthlmeterm

massmkilogramkg

timetseconds

electric currentIampereA

temperatureTkelvinK

(b)

III

1.8 MVV

21 m3cm3

6.8 nss

The above table shows some examples of quantities. Express the quantity in column I by using the unit in column II.1.8 MV = 1.8 x 106 V___________________________________________21 m3= 21 x 10-6 cm3 = 2.1 x 10-5 cm3____________________________6.8 ns= 6.8 x 10-9 s___________________________________________(c) Derive the unit for velocity and pressure.

Displacement

Force

Velocity = -----------------

Pressure =--------

Time

Area

=

=

=[m s1]

=Nm2

( The derived unit for velocity is m s-1. =Pa

( The derived unit for pressure is N m-2

(d) The S.I. unit for weight is given as N. Determine the relationship between weight and the

basic quantity.

Weight

= [kg m s2]

=[mass] [length]

[time]2

=[mass] [length]

[time] [time]2 Measuring apparatusSize of the object/cmSensitivity/cm

P1.80.1

Q1.830.01

R1.8320.001

The above table shows the size of an object that is measured using apparatus P, Q and R.(a) (i)Explain the meaning of the measuring apparatus sensitivity.

The sensitivity of a measuring apparatus is its ability to detect the physical quantity that it measures.

(ii)State the sensitivity of the measuring apparatus P, Q and R in the table above.

(b) Name the possible measuring apparatus for P, Q and R. P is a ruler; Q is a vernier calliper and R is a micrometer screw gauge.(c) Why doesnt the mercury thermometer give a very accurate temperature measurement

value? The principle of operation of a mercury thermometer is based on the expansion of the

mercury in the bulb. To expand the mercury, heat is required and it is obtained from the heat of the object whose temperature is being measured. Therefore, the temperature that is

shown by the mercury thermometer is less than the actual value. The expansion of the glass bulb can also produce an error during the measurement of the temperature.3

Load

W/NTime for 10 oscillations, t/sPeriod of oscillation, T/sT2/s2W/T2 N s-2

1.07.40.740.551.8

2.010.51.051.101.8

3.012.91.291.661.8

4.014.91.492.221.8

The above table shows the experimental data that is obtained by a student using the weighted spring oscillation system.

(a) Name the variable that is manipulated.

Weight of the load

(b) Name the variable that responds.

Period of oscillation

(c) Complete the above table with the corresponding values.(d) State the derived unit for W/T2.N s-2(e) Draw the graph of T2 against W.

(f) Interpret the shape of the graph that you have drawn.

Linear graph that passes through the origin

(g) Calculate the gradient of your graph.Graph gradient =

Inverse gradient =

= 0.55 s2 N1

= 1.8 N s2

(h) Write one relationship between the load and the period.

W/T2 = constant

4

(a)

(b)

Figure 5

Figure 5(a) shows the zero error for a micrometer screw gauge. Figure 5(b) shows the same micrometer screw gauge being used to measure the size of an object.(a) State the type and magnitude of the zero error for the micrometer screw gauge.The zero error is -0.04 mm

(b) What is the size of the object?

The size of the object = 3.47 mm - (-0.04 mm)

= 3.51 mm

(c) State two precautionary steps that must be taken when measuring with the micrometer screw gauge.

1 The ends of the gauges jaws are cleaned so that dirt stuck on it is not included in the measurement.

2 The ratchet is turned until the first tick sound is heard.

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