2021 - Physical Quantities and Units (Multiple Choice)

Physical quantities and units
1. What is a reasonable estimate for the density of sand?

a) 2 x 102 g/cm3
b) 2 x 103 g/cm3
c) 2 x 101 g/m3
d) 2 x 103 g/m3
2. Which physical quantity could have units of Ns2/m?

a) acceleration
b) force
c) mass
d) momentum
3. A velocity vector is shown.
What are the components of the velocity vector in the northerly and easterly directions?
North direction East direction

A 38 38
B 38 65
C 65 38
D 65 65
4. A micrometer screw gauge is used to measure the diameter of a copper wire. The reading with the
wire in position is shown in diagram 1. The wire is removed and the jaws of the micrometer are
closed. The new reading is shown in diagram 2.
What is the diameter of the wire?
a) 1.95 mm
b) 2.45 mm
c) 2.59 mm
d) 2.73 mm
5. A student measures the current and the potential difference for a resistor in a circuit.
current = (50.00 ± 0.01) mA
potential difference = (500.00 ± 0.1) mV
The measurements are used to calculate the resistance of the resistor. What is the percentage
uncertainty in the calculated resistance?
a) 0.0002%
b) 0.0004%
c) 0.02%
d) 0.04%
6. What is a reasonable estimate of the volume of an adult person?

a) 0.10 m3
b) 0.50 m3
c) 1.0 m3
d) 2.0 m3
7. What combination of units could be used for expressing the power dissipated in a resistor?
a) N/s
b) Ns
c) Nm
d) Nm/s
8. A force of 10 N and force of 5 N act on an object.
The resultant force on the object can be resolved into a pair of perpendicular components. Which
row shows numerical expressions for a possible pair of perpendicular components?
Force component Force component

A 10cos30 – 5 10cos30
B 10sin30 -5 10cos20
C 10 – 5cos30 5sin30
D 10 – 5sin30 5cos30
9. A micrometer screw gauge is used to measure the diameter of a wire. The reading on the
micrometer with the jaws closed is (-0.05 ± 0.02) mm. The reading with the wire in position
between the two jaws is (+1.03 ± 0.02) mm. What is the diameter of the wire?
a) (0.98 ± 0.02) mm
b) (1.08 ± 0.02) mm
c) (0.98 ± 0.04) mm
d) (1.08 ± 0.04) mm
10. What is not reasonable estimate of the physical property indicated?

a) 2 x 103 W for the power dissipated by the heating element of an elctric kettle
b) 4 x 102 m3 for the volume of water in a swimming pool
c) 5 x 105 Ns for the momentum of a lorry moving along a road
d) 6 x 102 N for the weight of a fully grown racehorse
11. Which quantity could have units of Nm/V?

a) acceleration
b) charge
c) current
d) resistance
12. An object is acted upon by two forces, 10 N in the vertical direction and 6 N at 40º to the vertical,
as shown.
What is the resultant force acting on the object?

13. An analogue ammeter with a range of 0 – 250 mA is connected into an electrical circuit. The
diagram shows the ammeter's display.
What is the reading on the ammeter?

a) 76 mA
b) 165 mA
c) 183 mA
d) 190 mA
14. Students take readings of the volume of a liquid using three different pieces of measuring
equipment X, Y and Z. The true value of the volume of the liquid is V. The students' results are
shown.
How many pieces of equipment are precise and how many are accurate?
no. of precise pieces of no. of accurate pieces of

equipment equipment
A 1 1
B 1 2
C 2 1
D 2 2
15. What is a unit of momentum?

a) kgm/s
b) N/s
c) Ns
d) kgs/m
16. What is the horizontal component of the force shown?
a) 12 N
b) 16 N
c) 25 N
d) 27 N
17. The diagram shows two readings on a micrometer.
What is the difference between the two readings?

a) 10.34 mm
b) 11.84 mm
c) 12.34 mm
d) 12.84 mm
18. The diameter of a circular disc is measured as (7.0 ± 0.1) mm. What is the area of the disc and the
absolute uncertainty in the area?
Area of disc (mm2) Absolute uncertainty (mm2)

A 38.5 ± 0.5
B 38 ±1
C 154 ±2
D 154 ±4
19. What is essential when recording a measurement of physical quantity?

a) the measurement has an SI unit
b) the measurement has a unit and a number
c) the measurement has a unit given as a base unit
d) the measurement is from an analogue scale
20. The mobility μ of electrons travelling through a metal conductor can be calculated using the
equation:
( )
where e is the charge of an electron and m is its mass. The average time between the collisions of
an electron with the atoms in the metal is . What are the SI base units of μ?
a) A/kg
b) As2/kg
c) As/kg
d) A/s2kg
21. An aircraft heads in a direction at an angle θ east of north with horizontal velocity relative to the
air of 800 km/h. The wind blows with horizontal velocity of 200 km/h from east to west, as
shown.
The resultant velocity of the aircraft is in a direction due north. What is angle and what is the magnitude
of the resultant force?
θ Resultant velocity (km(h)

A 14 770
B 14 820
C 76 770
D 76 820
22. A cathode-ray oscilloscope (CRO) is used to display a sound wave of frequency 2000 Hz. The
display of the CRO is shown.
What is the time-based setting on the CRO?

a) 125 μs/cm
b) 250 μs/cm
c) 500 μs/cm
d) 1000 μs/cm
23. Four possible sources of error in a series of measurement are listed.

1. an analogue meter whose scale is read from different angles
2. a meter which always measures 5% too high
3. a meter with needle that is not frictionless, so the needle sometimes sticks slightly
4. a meter with zero error
Which errors are random and which are systematic?

Random error Systematics error
A 1 and 2 3 and 4
B 1 and 3 2 and 4
C 2 and 4 1 and 3
D 3 and 4 1 and 2
24. Which row shows what all physical quantities must have?
Magnitude Direction Unit

A yes yes yes
B yes yes no
C yes no yes
D no no yes
25. What is an alternative way of expressing an energy of 43 dJ?

a) 4.3 x 103 mJ
b) 4.3 x 103 MJ
c) 4.3 x 10-3 mJ
d) 4.3 x 10-3 MJ
26. A tennis ball is hit so that it leaves the racket with velocity v at an angle θ to the horizontal.
The vertical component of the velocity is vy. What is the magnitude of the horizontal component
of v?
a) vsinθ
b) vycosθ
c) vysinθ
d) (v2-vy2)1/2
27. Four cathode-ray oscilloscope (CRO) screens each display a waveform. The screen and the time-
base setting of each CRO is shown.
What screen shows waveforms of the same frequency?

a) 1 and 2
b) 1 and 3
c) 1 and 4
d) 2 and 3
28. A student measures the time T for one complete oscillation of a pendulum of length l. Her results
are shown in the table.
l (m) T (s)
0.420 ± 0.001 1.3 ± 0.1
She used the formula:
to calculate the acceleration of free fall g. What is the best estimate of the percentage uncertainty
in the value of g?
a) 0.02%
b) 4%
c) 8%
d) 16%
29. A paperback book contains 210 sheets of paper (pages). Its thickness is measured with a ruler, as
shown.
What is the average thickess of one sheet of the paper in the book?
a) 0.013 mm
b) 0.017 mm
c) 0.13 mm
d) 0.17 mm
30. What is the unit of resistance when expressed in SI base unit?

a) kg-1 m-2 s A2
b) kg-1 m-2 s3 A2
c) kg m2 s-1 A-2
d) kg m2 s-3 A-2
31. Which list consists only of scalar quantities?

a) acceleration, displacement, force, weight
b) density, energy, frequency. velocity
c) distance, pressure, temperature, time
d) momentum, power, volume, wavelength
32. The output of a signal generator is connected to a cathode-ray oscilloscope (CRO). A trace is
shown on the screen.
The time-base of CRO the CRO is set at 2.0 ms/cm. What is the frequency of the signal?
a) 50 Hz
b) 125 Hz
c) 250 Hz
d) 500 Hz
33. After measuring the width of a shelf to be 305 mm, it is found that the graduations on the ruler
used are 1.0% further apart than they should be. Which type of measurement error is this and
what is the true width of the shelf?
Type or error True width (mm)

A random 302
B random 308
C systematic 302
D systematic 308
SOLUTIONS:
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

d c c b d a d c d d b d d d c
16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30.
a b b b b a a b c a d a d c d
31. 32. 33.
c b d

2021 - Physical Quantities and Units (Multiple Choice)

Uploaded by

Copyright:

Available Formats

2021 - Physical Quantities and Units (Multiple Choice)

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

2021 - Physical Quantities and Units (Multiple Choice)

Uploaded by

Copyright:

Available Formats

Physical quantities and units

1. What is a reasonable estimate for the density of sand?

2. Which physical quantity could have units of Ns2/m?

3. A velocity vector is shown.

North direction East direction

6. What is a reasonable estimate of the volume of an adult person?

8. A force of 10 N and force of 5 N act on an object.

Force component Force component

10. What is not reasonable estimate of the physical property indicated?

11. Which quantity could have units of Nm/V?

What is the resultant force acting on the object?

What is the reading on the ammeter?

no. of precise pieces of no. of accurate pieces of

15. What is a unit of momentum?

17. The diagram shows two readings on a micrometer.

What is the difference between the two readings?

Area of disc (mm2) Absolute uncertainty (mm2)

19. What is essential when recording a measurement of physical quantity?

θ Resultant velocity (km(h)

What is the time-based setting on the CRO?

23. Four possible sources of error in a series of measurement are listed.

Which errors are random and which are systematic?

Magnitude Direction Unit

25. What is an alternative way of expressing an energy of 43 dJ?

What screen shows waveforms of the same frequency?

She used the formula:

30. What is the unit of resistance when expressed in SI base unit?

31. Which list consists only of scalar quantities?

Type or error True width (mm)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

You might also like