Current Electricity · Question 81

An electric kettle takes 4 A current at 220 V. How much time will it take to boil 1 kg of water from temperature 20 ? The temperature of boiling water is 100

1. 12.6 min
2. 4.2 min
3. 6.3 min
4. 8.4 min

A current of 3 amp. flows through the 2 resistor shown in the circuit. The power dissipated in the 5 resistor is [figure]

1. 1 watt
2. 5 watt
3. 4 watt
4. 2 watt

Three resistances, P, Q, R each of 2 and an unknown resistance S form the four arms of a Wheatstone bridge circuit. When a resistance of 6 is connected in parallel to S the bridge gets balanced. What is the value of S?

1. 3
2. 6
3. 1
4. 2

The total power dissipated in watt in the circuit shown here is [figure]

1. 40
2. 54
3. 4
4. 16

In the circuit shown, if a conducting wire is connected between points A and B, the current in this wire will [figure]

1. flow from B to A
2. flow from A to B
3. flow in the direction which will be decided by the value of V
4. be zero

Kirchhoff's first and second laws of electrical circuits are consequences of

1. conservation of energy and electric charge respectively
2. conservation of energy
3. conservation of electric charge and energy respectively
4. conservation of electric charge

Two cells, having the same e.m.f. are connected in series through an external resistance R. Cells have internal resistances r1 and r2 (r1 > r2) respectively. When the circuit is closed, the potential difference across the first cell is zero. The value of R is

1. r1 + r2
2. r1 - r2
3. r1 + r22
4. r1 - r22

Power dissipated across the 8 Ω resistor in the circuit shown here is 2 watt. The power dissipated in watt units across the 3 Ω resistor is [figure]

1. 3.0
2. 2.0
3. 1.0
4. 0.5

Two batteries, one of emf 18 volts and internal resistance 2 and the other of emf 12 volts and internal resistance 1 , are connected as shown. The voltmeter V will record a reading of [figure]

1. 30 volt
2. 18 volt
3. 15 volt
4. 14 volt

When a wire of uniform cross-section a, length l and resistance R is bent into a complete circle, the resistance between any two diametrically opposite points will be

1. R/4
2. 4R
3. R/8
4. R/2