Dimensional analysis MCQ: Identify the pair of physical quantities that do not share identical dimensions. Out of the following pairs, determine which pair has different dimensional formula; assume standard M–L–T system for mechanics quantities. Choose the correct option.

Difficulty: Easy

Correct Answer: Power and energy

Explanation:


Given data

  • We compare dimensions of four pairs under the M–L–T system.


Concept/Approach
Use dimensional formulae: Force = MLT-2; Work/Energy = ML2T-2; Power = ML2T-3; Impulse = change of momentum = MLT-1; Pressure/Stress = ML-1T-2; Torque (moment of force) = ML2T-2.


Step-by-step check
Work vs torque ⇒ both ML2T-2 (identical).Impulse vs momentum ⇒ both MLT-1 (identical).Pressure vs stress ⇒ both ML-1T-2 (identical).Power vs energy ⇒ ML2T-3 vs ML2T-2 (different).


Common pitfalls
Confusing torque with power; torque shares dimensions with work/energy, but power includes per-unit-time.


Final Answer
Power and energy

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