JEE Physics 2025 Question with Solution

Given: Two statements about vernier callipers and vernier constant are to be checked.

Find: Which option correctly identifies the truth values of Statement I and Statement II.

For vernier calipers, the vernier constant is the difference between one main scale division and one vernier scale division.

Statement I: In a vernier callipers, one vernier scale division is always smaller than one main scale division.

In a vernier caliper, one vernier scale division is slightly smaller than one main scale division. This is the basic design that allows more precise measurement. Therefore, Statement I is true.

Statement II: The vernier constant is given by one main scale division multiplied by the number of vernier scale divisions.

The vernier constant is defined as:

$$\text{VC} = 1\,\text{MSD} - 1\,\text{VSD}$$

It is a difference, not a product. Therefore, Statement II is false.

Therefore, the correct option is B.

Given:

• Statement I: In a vernier callipers, one vernier scale division is always smaller than one main scale division.
• Statement II: The vernier constant is given by one main scale division multiplied by the number of vernier scale divisions.

Find: Determine the correct combination of truth values.

A vernier caliper works by comparing the main scale and the vernier scale. For the instrument to resolve small lengths, one vernier scale division must be slightly smaller than one main scale division. Hence Statement I is true.

The vernier constant or least count is given by the difference:

$$\text{Vernier Constant} = 1\,\text{MSD} - 1\,\text{VSD}$$

So the statement that it is obtained by multiplying one main scale division by the number of vernier scale divisions is incorrect. Hence Statement II is false.

Therefore, the correct answer is Statement I is true but Statement II is false, so the correct option is B.