In the following circuit, bulb rated as 1.5 V, 0.45 W. If bulbs glows with full intensity then what will be the equivalent resistance between X and Y-

Options

A. `0.45 Omega`
B. `1 Omega`
C. `3 Omega`
D. `5 Omega`

Answer

B

Explanation

When bulb glows with full intensity, then voltage across it will be 1.5 V and voltage across `3 Omega` resistance will be- 4.5 V

Current through `3 Omega` resistance ` i = 4.5/3 = 1.3 A`
Same current will flow between X and Y
So, `V_(XY) = iR_(XY) rArr 1.5 R_(XY) rArr R_(XY) = 1 Omega`