Units Dimensions And Measurement — DPP 1

20 NEET questions from Physics and Measurement, with answers and explanations. Attempt it as a timed test to get scoring, accuracy breakdown and mistake tracking.

Attempt this test free 20 questions · 30 minutes · +80 marks
1
Units of length, velocity and force are doubled. Which of the following is correct :-
  1. A Units of time is doubled
  2. B Unit of mass is doubled
  3. C Unit of momentum is doubled
  4. D Unit of energy is doubled
Show answer & explanation

Correct answer: C

Units Dimensions And Measurement – NEET-6041
2
Unit of energy in SI system is :-
  1. A erg
  2. B calorie
  3. C joule
  4. D electron volt
Show answer & explanation

Correct answer: C

Energy = Work
= (Force) (Displacement)
= N × m
= Joule
3
One nanometer is equal to :-
  1. A $10 ^ { 9 } \mathrm {~mm}$
  2. B $10 ^ { - 6 } \mathrm {~cm}$
  3. C $10 ^ { - 7 } \mathrm {~cm}$
  4. D $10 ^ { - 9 } \mathrm {~cm}$
Show answer & explanation

Correct answer: C

1 nanometer = 10$^{–9}$ m = 10$^{–7}$ cm
4
The units nanometre, fermi, angstrom and attometre, arranged in decreasing order will read as :-
  1. A angstrom, nanometre, fermi, attometre
  2. B fermi, attometre, angstrom, nanometre
  3. C nanometre, angstrom, fermi, attometre
  4. D attometre, angstrom, fermi, nanometer
Show answer & explanation

Correct answer: C

Angstrom = 10$^{–10}$ m, nanometre = 10$^{–9}$ m
Fermi = 10$^{–15}$ m, attometre = 10$^{–18}$ m
5
Which of the following is not a unit of time?
  1. A microsecond
  2. B leap year
  3. C lunar month
  4. D light year
Show answer & explanation

Correct answer: D

(a) 10$^{–6}$ sec
(b) 366 days
(c) 27.3 days
(d) 3.08 × 10$^{16}$ m (not the unit of time)
6
Temperature can be expressed as a derived quantity in terms of which of the following?
  1. A Length and mass
  2. B Mass and time
  3. C Length. mass and time
  4. D None of these
Show answer & explanation

Correct answer: D

Temperature being a fundamental quantity itself cannot be expressed in terms of any of these.
7
A dimensionless quantity
  1. A Never has a unit
  2. B Always has a unit
  3. C May have a unit
  4. D Does not exist
Show answer & explanation

Correct answer: C

Angle = Dimensionless but unit = radian relative density = Dimensionless and is unitless so dimensionless quantity may have a unit.
8
kg m/s$^{2}$ stand for the unit of :-
  1. A Energy
  2. B acceleration
  3. C Force
  4. D Momentum
Show answer & explanation

Correct answer: C

$\mathrm{F}=\mathrm{Ma}=\mathrm{Kg} \times \frac{\mathrm{m}}{\mathrm{sec}^{2}}$
9
Which of the following sets can not enter into the list of fundamental quantities in any system of units?
  1. A length, mass, velocity
  2. B length, time, velocity
  3. C length, time, mass
  4. D mass, time, velocity
Show answer & explanation

Correct answer: B

Velocity $=\frac{\text { displacement }}{\text { time }} \frac{\left(\mathrm{L}^{1}\right)}{\left(\mathrm{T}^{1}\right)}$
It can be derived from other two so it is a derived.
10
The surface tension of a liquid is 70 dynes/cm. It may be expressed in M.K.S. system as :-
  1. A 70 N/m
  2. B 7 × 10$^{–2}$ N/m
  3. C 7 × 10$^{2}$ N/m
  4. D 7 × 10$^{3}$ N/m
Show answer & explanation

Correct answer: B

$\begin{array}{l}1 \text { dyne }=10^{-5} \mathrm{~N} \\ 1 \mathrm{~cm}=10^{-2} \mathrm{~m} \\ \text { Surface Tension }=\frac{70 \text { dyne }}{\mathrm{cm}}=\frac{70 \times 10^{-5} \mathrm{~N}}{10^{-2} \mathrm{~m}} \\ \qquad=7 \times 10^{-2} \mathrm{~N} / \mathrm{m}\end{array}$
11
Which of the following is usually a derived quantity?
  1. A Mass
  2. B Velocity
  3. C Length
  4. D Time
Show answer & explanation

Correct answer: B

Velocity = [L$^{1}$T$^{–1}$] → derived
12
Which of the following is not a fundamental physical quantity?
  1. A Mass
  2. B Length
  3. C Temperature
  4. D Density
Show answer & explanation

Correct answer: D

Density is a derived quantity
Density = $\frac{\text { Mass }}{\text { Volume }}$
13
Which is the correct unit for measuring nuclear radii:-
  1. A micron
  2. B millimetre
  3. C agnstrom
  4. D fermi
Show answer & explanation

Correct answer: D

1 Fermi = 10$^{–15}$ meter
14
The SI unit of momentum is :-
  1. A $\frac { \mathrm { kg } } { \mathrm { m } }$
  2. B $\frac { \mathrm { kg } \cdot \mathrm { m } } { \mathrm { sec } }$
  3. C $\frac { \mathrm { kg } \cdot \mathrm { m } ^ { 2 } } { \mathrm { sec } }$
  4. D $\mathrm { kg } \times$ newton
Show answer & explanation

Correct answer: B

Momentum = mv = M$^{1}$L$^{1}$T$^{–1}$ = kg × m/sec.
15
SI unit of pressure is :-
  1. A pascal
  2. B Dyne/cm$^{2}$
  3. C cm of Hg
  4. D atmosphere
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Correct answer: A

Pressure $=\frac{\text { Force }}{\text { Area }}=\frac{\mathrm{N}}{\mathrm{m}^{2}}$
16
The unit of power is :-
  1. A kilowatt
  2. B kilowatt-hour
  3. C dyne
  4. D joule
Show answer & explanation

Correct answer: A

Power = $\frac{\text { Eerngy }}{\text { time }}$
= j/sec.
= Watt or Kilowatt
17
Kilowatt-hour is a unit of :-
  1. A electrical charge
  2. B energy
  3. C power
  4. D force
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Correct answer: B

Kilowatt hour = Power × time = Energy
18
In the SI system, the unit of temperature is :-
  1. A Degree centrigrade
  2. B Degree Celsius
  3. C Kelvin
  4. D Degree Fahrenheit
Show answer & explanation

Correct answer: C

Theory-Kelvin
19
The density of a liquid is 1000 kg m$^{–3}$. Its value in CGS system :-
  1. A 1 gcm$^{–3}$
  2. B 0.1 gcm$^{–3}$
  3. C 10 gcm$^{–3}$
  4. D 100 gcm$^{–3}$
Show answer & explanation

Correct answer: A

$\begin{aligned} \mathrm{d} & =10^{3} \mathrm{~kg} / \mathrm{m}^{3} \\ & =\frac{10^{3} \times 10^{3} \text { gram }}{10^{-6} \mathrm{~cm}^{3}}=1 \mathrm{gram} / \mathrm{cm}^{3}\end{aligned}$
20
N kg$^{-1}$ is the unit of :-
  1. A velocity
  2. B energy
  3. C acceleration
  4. D force
Show answer & explanation

Correct answer: C

$\frac{\mathrm{N}}{\mathrm{Kg}}=\frac{\text { Force }}{\text { Mass }}=$ Acceleration

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