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:

     

1.	from \(a\) to \(b\).
2.	from \(b\) to \(a\).
3.	from \(b\) to \(a\) through \(c\).
4.	from \(a\) to \(b\) through \(c\).

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. none of the above

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 emf 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

A voltmeter has resistance of 2000 ohms and it can measure upto 2V. If we want to increase its range to 10 V, then the required resistance in series will be 

1. 2000 Ω

2. 4000 Ω

3. 6000 Ω

4. 8000 Ω

In the given figure, battery E is balanced on 55 cm length of potentiometer wire but when a resistance of 10 Ω is connected in parallel with the battery then it balances on 50 cm length of the potentiometer wire then internal resistance r of the battery is 

1. 1 Ω

2. 3 Ω

3. 10 Ω

4. 5 Ω