AB is a wire of uniform resistance. The galvanometer G shows no current when the length AC = 20cm and CB = 80 cm. The resistance R is equal to 

(1) 2 Ω

(2) 8 Ω

(3) 20 Ω

(4) 40 Ω

The circuit shown here is used to compare the e.m.f. of two cells $E_1$ and $E_2(E_1>E_2)$. The null point is at C when the galvanometer is connected to E₁. When the galvanometer is connected to E₂, the null point will be 

(1) To the left of C

(2) To the right of C

(3) At C itself

(4) Nowhere on AB

In the Wheatstone's bridge (shown in the figure below) X = Y and A > B. The direction of the current between a and b will be:

A resistance of 4 Ω and a wire of length 5 metres and resistance 5 Ω are joined in series and connected to a cell of e.m.f. 10 V and internal resistance 1 Ω. A parallel combination of two identical cells is balanced across 300 cm of the wire. The e.m.f. E of each cell is:

1. 1.5 V

2. 3.0 V

3. 0.67 V

4. 1.33 V

Constantan wire is used in making standard resistances because of its :

(1) Specific resistance is low

(2) Density is high

(3) Temperature coefficient of resistance is negligible

(4) Melting point is high

A potentiometer consists of a wire of length 4 m and resistance 10 Ω. It is connected to a cell of e.m.f. 2 V. The potential difference per unit length of the wire will be :

(1) 0.5 V/m

(2) 2 V/m

(3) 5 V/m

(4) 10 V/m

In the circuit shown $P\ne R$, the reading of the galvanometer is same with switch S open or closed. Then 

(1) $I_R=I_G$

(2) $I_P=I_G$

(3) $I_Q=I_G$

(4) $I_Q=I_R$

In the following Wheatstone bridge $P/Q=R/S$. If key K is closed, then the galvanometer will show deflection :

(1) In left side

(2) In right side

(3) No deflection

(4) In either side

In a potentiometer experiment, the galvanometer shows no deflection when a cell is connected across 60 cm of the potentiometer wire. If the cell is shunted by a resistance of 6 Ω, the balance is obtained across 50 cm of the wire. The internal resistance of the cell is 

(1) 0.5 Ω

(2) 0.6 Ω

(3) 1.2 Ω

(4) 1.5 Ω

In the circuit given below, the e.m.f. of the cell is 2 volt and the internal resistance is negligible. The resistance of the voltmeter is 80 ohm. The reading of the voltmeter will be:                                 
1. 0.80 volt

2. 1.60 volt

3. 1.33 volt

4. 2.00 volt