In the circuit, the galvanometer G shows zero deflection. If the batteries A and B have negligible internal resistance, the value of the resistor R will be :

Question

In the circuit, the galvanometer G shows zero deflection. If the batteries A and B have negligible internal resistance, the value of the resistor R will be : (A) 200 Ω (B) 100 Ω (C) 500 Ω (D) 1000 Ω

Tardigrade Admin · Accepted Answer

The galvanometer shows zero deflection, i.e., current through

X Y

is zero
As a result potential drop across

R

is

2 V

circuit can be redrawn as

I = \frac{12}{500 + R}

Voltage across

R, V = I R

\Rightarrow 2 = \frac{12}{500 + R} \times R

\Rightarrow 1000 + 2 R = 12 R \Rightarrow R = 100 Ω

Q. In the circuit, the galvanometer $G$ shows zero deflection. If the batteries $A$ and $B$ have negligible internal resistance, the value of the resistor $R$ will be :

$200 Ω$

$100 Ω$

$500 Ω$

$1000 Ω$

Q. In the circuit, the galvanometer G shows zero deflection. If the batteries A and B have negligible internal resistance, the value of the resistor R will be :

200Ω

100Ω

500Ω

1000Ω

The galvanometer shows zero deflection, i.e., current through XY is zero As a result potential drop across R is 2V circuit can be redrawn as I=500+R12​ Voltage across R,V=IR ⇒2=500+R12​×R ⇒1000+2R=12R⇒R=100Ω

Q. In the circuit, the galvanometer $G$ shows zero deflection. If the batteries $A$ and $B$ have negligible internal resistance, the value of the resistor $R$ will be :

$200 Ω$

$100 Ω$

$500 Ω$

$1000 Ω$