UNITS AND MEASUREMENT MCQS – NEET PHYSICS NCERT – CLASS 11
1. Which of the following is a fundamental quantity?
A. Force
B. Temperature
C. Work
D. Energy
Answer: B. Temperature
Explanation: Temperature is a base (fundamental) physical quantity in the SI system.
2. Which of these is a derived quantity?
A. Mass
B. Length
C. Area
D. Time
Answer: C. Area
Explanation: Area is derived from the product of two lengths (length × breadth).
3. What is the SI unit of electric current?
A. Coulomb
B. Volt
C. Ampere
D. Watt
Answer: C. Ampere
Explanation: Ampere is the SI base unit of electric current.
4. Which of the following has different units than the rest?
A. Work
B. Energy
C. Torque
D. Power
Answer: D. Power
Explanation: Power has units of watts (J/s), while the others have joules.
5. Which of the following is NOT a correct pair of quantity and unit?
A. Force – Newton
B. Power – Joule
C. Pressure – Pascal
D. Energy – Joule
Answer: B. Power – Joule
Explanation: Power is measured in watts, not joules.
6. Dimensional formula of velocity is:
A. [L¹T⁻¹]
B. [LT²]
C. [MLT⁻²]
D. [MLT]
Answer: A. [L¹T⁻¹]
Explanation: Velocity = displacement/time = [L]/[T].
7. The number of significant figures in 0.004560 is:
A. 3
B. 4
C. 5
D. 6
Answer: C. 4
Explanation: Only non-zero digits and zeros after a decimal count: 4, 5, 6, and the final 0.
8. Which of the following is a correct dimensional formula for force?
A. [MLT⁻¹]
B. [ML²T⁻²]
C. [MLT⁻²]
D. [M⁻¹L⁻²T²]
Answer: C. [MLT⁻²]
Explanation: Force = mass × acceleration = [M][LT⁻²].
9. The number 2.300 × 10³ has how many significant figures?
A. 2
B. 3
C. 4
D. 5
Answer: C. 4
Explanation: All non-zero digits and zeros between or after decimals are significant.
10. The dimensional formula of work is:
A. [ML²T⁻²]
B. [MLT⁻²]
C. [MT⁻²]
D. [ML⁻¹T²]
Answer: A. [ML²T⁻²]
Explanation: Work = Force × Displacement = [MLT⁻²] × [L] = [ML²T⁻²].
11. Which physical quantity has dimensions [MLT⁻²]?
A. Velocity
B. Acceleration
C. Force
D. Pressure
Answer: C. Force
Explanation: Force = mass × acceleration, hence [MLT⁻²].
12. Which of the following is not a derived quantity?
A. Acceleration
B. Pressure
C. Time
D. Work
Answer: C. Time
Explanation: Time is a fundamental quantity.
13. 1 femtometer equals:
A. 10⁻¹² m
B. 10⁻¹⁵ m
C. 10⁻⁶ m
D. 10⁻⁹ m
Answer: B. 10⁻¹⁵ m
Explanation: Femto- denotes 10⁻¹⁵.
14. Which pair has the same dimensions?
A. Work and Torque
B. Energy and Power
C. Pressure and Force
D. Power and Velocity
Answer: A. Work and Torque
Explanation: Both have dimensions [ML²T⁻²].
15. If two quantities have the same dimensions, they:
A. Must represent the same physical concept
B. May or may not represent the same physical concept
C. Cannot represent different concepts
D. Are always equal in magnitude
Answer: B. May or may not represent the same physical concept
Explanation: Torque and Work have the same dimensions but are different in nature.
16. Which is the correct unit of pressure in the SI system?
A. N/m
B. N
C. N/m²
D. J/m³
Answer: C. N/m²
Explanation: Pressure = Force/Area = Newton per square meter = Pascal (Pa).
17. How many significant figures are there in 120.00?
A. 2
B. 3
C. 4
D. 5
Answer: D. 5
Explanation: All digits including trailing zeros after the decimal point are significant.
18. Which of the following methods can be used to find the dimensions of a physical quantity?
A. Unitary method
B. Dimensional analysis
C. Vector algebra
D. Integration
Answer: B. Dimensional analysis
Explanation: Dimensional analysis is used to find dimensions and verify equations.
19. A dimensionless quantity is:
A. Always a constant
B. Never a vector
C. Has no units
D. Has infinite dimensions
Answer: C. Has no units
Explanation: A dimensionless quantity is a pure number, without physical dimensions.
20. What is the dimensional formula of momentum?
A. [MLT⁻²]
B. [ML²T⁻²]
C. [MLT⁻¹]
D. [M²L²T⁻²]
Answer: C. [MLT⁻¹]
Explanation: Momentum = mass × velocity = [M][LT⁻¹].
21. The accuracy of a measurement is limited by:
A. Instrument
B. Human error
C. Method
D. All of the above
Answer: D. All of the above
Explanation: All factors contribute to the accuracy of measurements.
22. Which quantity has units of J/kg·K?
A. Specific heat capacity
B. Thermal conductivity
C. Heat
D. Entropy
Answer: A. Specific heat capacity
Explanation: It’s the amount of heat per unit mass per unit temperature.
23. SI unit of luminous intensity is:
A. Watt
B. Lux
C. Candela
D. Lumen
Answer: C. Candela
Explanation: Candela is the SI unit of luminous intensity.
24. What is the SI unit of Planck’s constant?
A. Js
B. N·m
C. J/s
D. m/s
Answer: A. Js
Explanation: Planck’s constant = Energy × Time = Joule·second.
25. Which one of the following pairs has the same dimensions?
A. Pressure and Energy
B. Torque and Energy
C. Power and Energy
D. Work and Power
Answer: B. Torque and Energy
Explanation: Both have [ML²T⁻²].
26. Which measurement has 3 significant figures?
A. 0.070
B. 70
C. 700
D. 7.00
Answer: D. 7.00
Explanation: Trailing zeros after a decimal are significant.
27. The radius of an atom is of the order of:
A. 10⁻⁶ m
B. 10⁻⁸ m
C. 10⁻¹⁰ m
D. 10⁻¹² m
Answer: C. 10⁻¹⁰ m
Explanation: Atomic radius is typically around 0.1 nm or 1 Å.
28. Dimensional formula of energy is same as:
A. Power
B. Force
C. Work
D. Pressure
Answer: C. Work
Explanation: Energy and work both = [ML²T⁻²].
29. Which of these quantities is vector and has dimension [LT⁻²]?
A. Velocity
B. Displacement
C. Acceleration
D. Momentum
Answer: C. Acceleration
Explanation: Acceleration is the rate of change of velocity and has [LT⁻²].
30. Which of the following cannot be determined using dimensional analysis?
A. To check the correctness of formula
B. To convert units
C. To find numerical constants
D. To find relationships
Answer: C. To find numerical constants
Explanation: Dimensional analysis cannot determine pure numbers or constants.
31. A derived quantity is expressed in terms of:
A. Only SI base units
B. Combination of fundamental units
C. Arbitrary units
D. None of the above
Answer: B. Combination of fundamental units
Explanation: Derived quantities come from combinations of fundamental units.
32. One liter is equal to:
A. 10⁻³ m³
B. 10³ cm³
C. Both A and B
D. None
Answer: C. Both A and B
Explanation: 1 L = 1000 cm³ = 10⁻³ m³.
33. The SI unit of solid angle is:
A. Degree
B. Radian
C. Steradian
D. None
Answer: C. Steradian
Explanation: Steradian is the unit of solid angle.
34. Which of the following does not have dimensions?
A. Strain
B. Velocity
C. Pressure
D. Force
Answer: A. Strain
Explanation: Strain is a ratio and hence dimensionless.
35. What is the dimensional formula for power?
A. [ML²T⁻²]
B. [ML²T⁻³]
C. [MLT⁻²]
D. [MLT⁻¹]
Answer: B. [ML²T⁻³]
Explanation: Power = Work/Time = [ML²T⁻²]/[T] = [ML²T⁻³].
36. Which of the following is the largest unit of length?
A. Meter
B. Kilometer
C. Astronomical Unit
D. Light Year
Answer: D. Light Year
Explanation: A light-year is the distance light travels in one year.
37. SI unit of density is:
A. kg/m
B. kg/m²
C. kg/m³
D. g/cm³
Answer: C. kg/m³
Explanation: Density = Mass/Volume = kg/m³.
38. The number of base units in SI system is:
A. 5
B. 6
C. 7
D. 8
Answer: C. 7
Explanation: There are 7 fundamental/base quantities.
39. Which of these is not a base quantity in SI?
A. Luminous intensity
B. Electric current
C. Pressure
D. Temperature
Answer: C. Pressure
Explanation: Pressure is derived; the rest are fundamental.
40. Planck’s constant has dimensions of:
A. [ML²T⁻²]
B. [ML²T⁻¹]
C. [MLT⁻²]
D. [MLT⁻¹]
Answer: B. [ML²T⁻¹]
Explanation: Energy × Time = [ML²T⁻²] × [T] = [ML²T⁻¹].
41. What is the dimensional formula of angular momentum?
A. [ML²T⁻²]
B. [ML²T⁻¹]
C. [MLT⁻²]
D. [MLT⁻¹]
Answer: B. [ML²T⁻¹]
Explanation: Angular momentum = I × ω → [ML²T⁻¹].
42. Unit of gravitational constant G is:
A. Nm²/kg²
B. N/kg²
C. Nm²/s²
D. N/kg
Answer: A. Nm²/kg²
Explanation: From F = Gm₁m₂/r² → G = Fr²/m₁m₂.
43. The dimensional formula of modulus of elasticity is same as:
A. Force
B. Pressure
C. Energy
D. Work
Answer: B. Pressure
Explanation: Modulus = Stress/Strain = Pressure.
44. Which instrument is used for the most accurate measurement of length?
A. Meter scale
B. Vernier caliper
C. Screw gauge
D. Ruler
Answer: C. Screw gauge
Explanation: Screw gauge has the least count of 0.01 mm.
45. A quantity has units kg·m/s². It represents:
A. Work
B. Power
C. Pressure
D. Force
Answer: D. Force
Explanation: kg·m/s² = Newton = Force.
46. The SI unit of time is defined using:
A. Solar day
B. Cesium atomic clock
C. Mean solar day
D. Pendulum
Answer: B. Cesium atomic clock
Explanation: Time is now defined based on cesium-133 transitions.
47. Which one is not a correct conversion?
A. 1 m = 100 cm
B. 1 km = 1000 m
C. 1 cm = 10 mm
D. 1 mm = 100 μm
Answer: D. 1 mm = 100 μm
Explanation: 1 mm = 1000 μm.
48. What is the dimensional formula of surface tension?
A. [MT⁻²]
B. [ML⁻¹T⁻²]
C. [MLT⁻²]
D. [ML⁻²T⁻²]
Answer: B. [ML⁻¹T⁻²]
Explanation: Surface tension = Force/Length = [MLT⁻²]/[L].
49. Which of the following has dimension of [MLT⁻³]?
A. Work
B. Pressure
C. Power
D. None
Answer: D. None
Explanation: No standard quantity has [MLT⁻³].
50. Which quantity is not dimensionless?
A. Strain
B. Relative density
C. Refractive index
D. Velocity
Answer: D. Velocity
Explanation: Velocity has dimensions of [LT⁻¹].