If 50 Vernier divisions are equal to 49 main scal divisions of a travelling microscope and on smallest reading of main scale is 0.5 mm, th Vernier constant of travelling microscope is:

The Vernier constant (VC) of a travelling microscope can be calculated using the formula:

VC = (Value of one main scale division) - (Value of one Vernier scale division)

Given that 50 Vernier divisions are equal to 49 main scale divisions, we can say that the value of one Vernier scale division is equal to (49/50) of one main scale division.

Also, we know that the smallest reading of the main scale is 0.5 mm. Therefore, the value of one main scale division is 0.5 mm.

Substituting these values into the formula, we get:

VC = 0.5 mm - (49/50)*0.5 mm VC = 0.5 mm - 0.49 mm VC = 0.01 mm

Therefore, the Vernier constant of the travelling microscope is 0.01 mm.