JEE Physics 2025 Question with Solution

Given: We need to identify the pair of physical quantities that do not have the same dimensions.

Find: The correct option.

Compare the dimensions of each pair:

• Torque: $[M L^2 T^{-2}]$

• Energy: $[M L^2 T^{-2}]$ So, these have the same dimensions.

• Pressure: $[M L^{-1} T^{-2}]$

• Young's modulus: $[M L^{-1} T^{-2}]$ So, these also have the same dimensions.

• Angular momentum: $[M L^2 T^{-1}]$

• Planck's constant: $[M L^2 T^{-1}]$ So, these have the same dimensions.

• Surface tension: $[M T^{-2}]$

• Impulse: $[M L T^{-1}]$ These are different.

Therefore, the pair not having the same dimensions is Surface tension and impulse. The correct option is D.

The solution states option A, but the dimensional comparison shown in the working clearly proves that D is correct.

Given: A dimension comparison question.

Find: The mismatched pair.

A quick check shows that the first three pairs are standard equal-dimension pairs:

• Torque and energy
• Pressure and Young's modulus
• Angular momentum and Planck's constant

For the last pair:

• Surface tension $= \frac{\text{force}}{\text{length}} = [M T^{-2}]$
• Impulse $= \text{force} \times \text{time} = [M L T^{-1}]$

Since these differ, the correct option is D.