If the galvanometer in the circuit of figure reads zero, calculate the value of the resistor R (ion `Komega`) assuming that the 12 V source has negligble internal resistance.

Options

A. `1000 Omega`
B. `2000 Omega`
C. `1500 Omega`
D. `3500 Omega`

Answer

B

Explanation

The galvanometer shos zero deflection.
`therefore` P.D. across R=2V.
If I is the current in the circuit, then
`V=IR=2 V therefore I=(2)/(R )`
But `I=(12)/(10xx10^(3)+R)`
`therefore (2)/(R) =(12)/(10^(4)+R)`
`therefore 12 R=2xx10^(4)+2 R therefore 10 R=2xx10^(4)`
`therefore R=2000 Omega`