AB is a potentiometer wire of length 100 cm and its resistance is 10 ohms. It is connected in series with a resistance R = 40 ohms and a battery of e.m.f. 2 V and negligible internal resistance. If a source of unknown e.m.f. E is balanced by 40 cm length of the potentiometer wire, the value of E is  

1. 0.8 V

2. 1.6 V

3. 0.08 V

4. 0.16 V

The measurement of the voltmeter in the following circuit is :

1. 2.4 V

2. 3.4 V

3. 4.0 V

4. 6.0 V

The potential difference across the 100Ω resistance in the following circuit is measured by a voltmeter of 900 Ω resistance. The percentage error made in reading the potential difference is :

1. $\frac{10}{9}$

2. 0.1

3. 1.0

4. 10.0

If the ammeter in the given circuit reads 2 A, the resistance R is :

1. 1 ohm

2. 2 ohm

3. 3 ohm

4. 4 ohm

Two resistances of 400 Ω and 800 Ω are connected in series with a 6-volt battery of negligible internal resistance. A voltmeter of resistance 10,000 Ω is used to measure the potential difference across 400 Ω. The error in the measurement of potential difference in volts approximately is :

1. 0.01

2. 0.02

3. 0.03

4. 0.05

The length of a wire of a potentiometer is \(100~\text{cm}\), and the emf of its standard cell is \(E\) volt. It is employed to measure the emf of a battery whose internal resistance is \(0.5~\Omega\). If the balance point is obtained at \(l = 30~\text{cm}\) from the positive end, the emf of the battery is:
1. \(\frac{30E}{100}\)
2. \(\frac{30E}{100.5}\)
3. \(\frac{30E}{(100-0.5)}\)
4. \(\frac{30(E-0.5i)}{100}, \) where \(i\) is the current in the potentiometer

What is the reading of the voltmeter in the following figure?

1. 3 V

2. 2 V

3. 5 V

4. 4 V

In a metre bridge experiment, the null point is obtained at 20 cm from one end of the wire when resistance X is balanced against another resistance Y. If X < Y, then where will be the new position of the null point from the same end, if one decides to balance a resistance of 4X against Y 

1. 50 cm

2. 80 cm

3. 40 cm

4. 70 cm

In given figure, the potentiometer wire AB has a resistance of 5 Ω and length 10 m. The balancing length AM for the emf of 0.4 V is :

1. 0.4 m

2. 4 m

3. 0.8 m

4. 8 m

If the resistance of voltmeter is 10000Ω and resistance of ammeter is 2Ω then find R when voltmeter reads 12V and ammeter reads 0.1 A :

1. 118 Ω

2. 120 Ω

3. 124 Ω

4. 114Ω