The potential gradient along the length of a uniform wire is \(10~\text{V/m}\). \(B\) and \(C\) are the two points at \(30~\text{cm}\) and \(60~\text{cm}\) point on a meter scale fitted along the wire. The potential difference between \(B\) and \(C\) will be:
1. \(3~\text{V}\)
2. \(0.4~\text{V}\)
3. \(7~\text{V}\)
4. \(4~\text{V}\)

When a \(12~\Omega\) resistor is connected in parallel with a moving coil galvanometer, its deflection reduces from \(50\) divisions to \(10\) divisions. What will be the resistance of the galvanometer?
1. \(24~\Omega\)
2. \(36~\Omega\)
3. \(48~\Omega\)
4. \(60~\Omega\)

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

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

If the length of the potentiometer wire is increased, then the length of the previously obtained balance point will :

(1) Increase

(2) Decrease

(3) Remain unchanged

(4) Become two times

If in the experiment of Wheatstone's bridge, the positions of cells and galvanometer are interchanged, then balance points will

(1) Change

(2) Remain unchanged

(3) Depend on the internal resistance of cell and resistance of galvanometer

(4) None of these

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

A voltmeter has a resistance of G ohms and range V volts. The value of resistance used in series to convert it into a voltmeter of range nV volts is :

(1) nG

(2) $(n-1)G$

(3) $\frac{G}{n}$ 

(4) $\frac{G}{(n-1)}$