Three equal resistances each of value R are joined as shown in the figure. The equivalent resistance between M and N is 

1. R

2. 2R

3. $\frac{R}{2}$

4. $\frac{R}{3}$

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

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 order to pass 10% of the main current through a moving coil galvanometer of 99 ohms, the resistance of the required shunt is :

1. 9.9 Ω

2. 10 Ω

3. 11 Ω

4. 9 Ω

A galvanometer can be used as a voltmeter by connecting a :

1. High resistance in series

2. Low resistance in series

3. High resistance in parallel

4. Low resistance in parallel

A potentiometer is used for the comparison of e.m.f. of two cells E₁ and E₂. For cell E₁ the no deflection point is obtained at 20cm and for E₂ the no deflection point is obtained at 30cm. The ratio of their e.m.f.'s will be 

1. 2/3

2. 1/2

3. 1

4. 2

Two cells when connected in series are balanced on 8m on a potentiometer. If the cells are connected with polarities of one of the cells  reversed, they balance on 2m. The ratio of e.m.f.'s of the two cells is

1. 3 : 5

2. 5 : 3

3. 3 : 4

4. 4 : 3

In the diagram shown, the reading of voltmeter is 20 V and that of ammeter is 4 A. The value of R should be (consider given ammeter and voltmeter are not ideal) :

1. Equal to 5 Ω

2. Greater from 5 Ω

3. Less than 5 Ω

4. Greater or less than 5 Ω depends on the material of R

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

A light bulb, a capacitor and a battery are connected together as shown below with the switch S initially open. When the switch S is closed, which one of the following is true?

1. The bulb will light up for an instant when
    the capacitor starts charging.
2. The bulb will light up when
    the capacitor is fully charged.
3. The bulb will not light up at all.
4. The bulb will light up and go off at regular intervals.