Two sources of equal emf are connected to an external resistance R. The internal resistances of the two sources are R₁ and $R_2(R_2>R_1)$. If the potential difference across the source having internal resistance R₂ is zero, then 

(1) $R=R_1{R}_2/(R_1+R_2)$

(2) $R=R_1{R}_2/(R_2-R_1)$

(3) $R=R_2\times (R_1+R_2)/(R_2-R_1)$

(4) $R=R_2-R_1$

The magnitude of i in ampere unit is 

(1) 0.1

(2) 0.3

(3) 0.6

(4) None of these

To draw maximum current from a combination of cells, how should the cells be grouped 

(1) Series

(2) Parallel

(3) Mixed

(4) Depends upon the relative values of external and internal resistance

By ammeter, which of the following can be measured 

(1) Electric potential

(2) Potential difference

(3) Current

(4) Resistance

The resistance of \(1~\text{A}\) ammeter is \(0.018~\Omega\). To convert it into \(10~\text{A}\) ammeter, the shunt resistance required will be:
1. \(0.18~\Omega\)
2. \(0.0018~\Omega\)
3. \(0.002~\Omega\)
4. \(0.12~\Omega\)

For measurement of potential difference, the potentiometer is preferred in comparison to the voltmeter because:

1. the potentiometer is more sensitive than the voltmeter.

2. the resistance of the potentiometer is less than
    the voltmeter.

3. the potentiometer is cheaper than the voltmeter.

4. the potentiometer does not take current from the circuit.

In Wheatstone's bridge P = 9 ohm, Q = 11 ohm, R = 4 ohm and S = 6 ohm. How much resistance must be put in parallel to the resistance S to balance the bridge 

(1) 24 ohm

(2) $\frac{44}{9}$ohm

(3) 26.4 ohm

(4) 18.7 ohm

A potentiometer is an ideal device of measuring potential difference because

(1) It uses a sensitive galvanometer

(2) It does not disturb the potential difference it measures

(3) It is an elaborate arrangement

(4) It has a long wire hence heat developed is quickly radiated

A battery of 6 volts is connected to the terminals of a three metre long wire of uniform thickness and resistance of the order of 100 Ω. The difference of potential between two points separated by 50cm on the wire will be :

(1) 1 V

(2) 1.5 V

(3) 2 V

(4) 3 V