In the meter bridge circuit, the length AB for Null deflection in galvanometer, is 50 cm. Value of resistance r, is a. 10 Ω b. 15 Ω c. 30 Ω d. 20 Ω

Substituting these values

15x/ (15 + x) = 10

By further calculation

15x = 10 (15 + x)

15x = 150 + 10x

15x - 10x = 150

5x = 150

Dividing both sides by 5

x = 30 Ω

Therefore, the value of resistance r is 30 Ω.

Summary:

In the meter bridge circuit, the length AB for Null deflection in the galvanometer is 50 cm. Value of resistance r is

In the meter bridge circuit, the length AB for Null deflection in the galvanometer is 50 cm. The value of resistance r is 30 Ω.