In the adjoining circuit, the battery E₁ has an e.m.f. of 12 volts and zero internal resistance while the battery E has an e.m.f. of 2 volts. If the galvanometer G reads zero, then the value of the resistance X in ohm is 

1. 10

2. 100

3. 500

4. 200

The magnitude and direction of the current in the circuit shown will be 

1. $\frac{7}{3}$A from a to b through e

2. $\frac{7}{3}$A from b to a through e

3. 1A from b to a through e

4. 1A from a to b through e

The e.m.f. of a cell is E volts and internal resistance is r ohm. The resistance in external circuit is also r ohm. The p.d. across the cell will be 

1. E/2

2. 2E

3. 4E

4. E/4

Kirchhoff's first law i.e. $\Sigma i=0$ at a junction is based on the law of conservation of :

1. Charge

2. Energy

3. Momentum

4. Angular momentum

The figure below shows currents in a part of electric circuit. The current i is

1. 1.7 amp

2. 3.7 amp

3. 1.3 amp

4. 1 amp

In the circuit shown, A and V are ideal ammeter and voltmeter respectively. Reading of the voltmeter will be

1. 2 V

2. 1 V

3. 0.5 V

4. Zero

The terminal potential difference of a cell when short-circuited is (E = E.M.F. of the cell)

1. E

2. E/2

3. Zero

4. E/3

The potential difference in open circuit for a cell is 2.2 volts. When a 4-ohm resistor is connected between its two electrodes the potential difference becomes 2 volts. The internal resistance of the cell will be :

1. 1 ohm

2. 0.2 ohm

3. 2.5 ohm

4. 0.4 ohm

A cell whose e.m.f. is 2 V and internal resistance is 0.1 Ω, is connected with a resistance of 3.9 Ω. The voltage across the cell terminal will be :

1. 0.50 V

2. 1.90 V

3. 1.95 V

4. 2.00 V

n identical cells each of e.m.f. E and internal resistance r are connected in series. An external resistance R is connected in series to this combination. The current through R is 

1. $\frac{nE}{R+nr}$

2. $\frac{nE}{nR+r}$

3. $\frac{E}{R+nr}$

4. $\frac{nE}{R+r}$