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

The resistance of an ideal voltmeter is 

(1) Zero

(2) Very low

(3) Very large

(4) Infinite

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

The net resistance of a voltmeter should be large to ensure that :

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

A galvanometer having a resistance of \(8~\Omega\) is shunted by a wire of resistance \(2~\Omega\). If the total current is \(1~\text{A}\), the part of it passing through the shunt will be:
1. \(0.25~\text{A}\)
2. \(0.8~\text{A}\)
3. \(0.2~\text{A}\)
4. \(0.5~\text{A}\)

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