JEE Physics 2026 Question with Solution

Given: Match the physical quantities in LIST-I with their dimensions in LIST-II.

Find: The correct matching.

Step 1: Identify dimensions of each physical quantity using defining equations.

For spring constant,

$$k = \frac{F}{x}$$

So,

$$[k] = \frac{MLT^{-2}}{L} = ML^0T^{-2}$$

Hence A \rightarrow II.

For thermal conductivity,

$$[K] = MLT^{-3}K^{-1}$$

Hence B \rightarrow IV.

For Boltzmann constant,

$$[k_B] = ML^2T^{-2}K^{-1}$$

Hence C \rightarrow I.

For inductive reactance,

$$X_L = \omega L$$

Its dimensions are

$$ML^2T^{-3}A^{-2}$$

Hence D \rightarrow III.

Step 2: Match with LIST-II.

$$\text{A-II, B-IV, C-I, D-III}$$

Therefore, the correct option is A.

Given: Four physical quantities and four dimensional formulas.

Find: Which option gives the correct correspondence.

Use dimensional analysis for each term instead of memorizing the list.

1. Spring constant comes from Hooke's law.

$$F = kx$$

Therefore,

$$k = \frac{F}{x}$$

and

$$[k] = \frac{MLT^{-2}}{L} = ML^0T^{-2}$$

So A-II.

2. Thermal conductivity has dimensional formula

$$MLT^{-3}K^{-1}$$

So B-IV.

3. Boltzmann constant relates energy to temperature, so its dimensions are energy per temperature.

$$[k_B] = \frac{ML^2T^{-2}}{K} = ML^2T^{-2}K^{-1}$$

So C-I.

4. Inductive reactance is measured in ohm. From

$$X_L = \omega L$$

it has dimensions of resistance:

$$ML^2T^{-3}A^{-2}$$

So D-III.

Thus the full matching is A-II, B-IV, C-I, D-III.

Therefore, the correct option is A.