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Two metallic wires of the same material and same length have different diameters. If we connect them in series across a battery, the heat produced is H1, If we connect them in parallel to the same battery, the heat produced during the same time is H2. From the above, we infer that

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Important Questions on Current Electricity

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

A heater coil is cut into two equal parts and only one part is used for heating. The heat generated will now be

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

An electric bulb is marked $220 V, 100 W$ . When it is connected across $110 V$ , its power is:

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

A circuit has a resistance of

12 Ω

and an impedance of

15 Ω

. The power factor of the circuit will be

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

Two resistors of resistance,

100 Ω

and

200 Ω

are connected in parallel in an electrical circuit. The ratio of the thermal energy developed in

100 Ω

to that in

200 Ω

in a given time is

EASY

Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

Two electric bulbs rated

P_{1}

watt,

V

volts and

P_{2}

watt,

V

volts are connected in parallel and

V

volts are applied to it. The total power will be :-

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

n

identical bulbs, each designed to draw a power

P

from a supply, are joined in series across the same supply. The total power which they draw is

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

An electric bulb is rated

220 volt, 100 watt

. Power consumed by it when operated on

110 volt

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

$A D C$ source with internal resistance $R_{0}$ is connected to circuit as shown in the figure. The value of $R$ for which the power generated in the circuit is the maximum is

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

A resistor develops

500 J

of thermal energy in

20 s

when a current of

1.5 A

is passed through it. If the current is increased from

1.5 A

3 A

, what will be the energy developed in

20 s

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

An electric bulb is rated

220 V

and

100 W

. What is the power consumed by it when operated on

110 V ?

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

In the circuit shown, the resistance r is a variable resistance. If for

r = f R

, the heat generation in r is maximum then the value of

f

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

If the current through a resistor in a circuit increases by

3 %,

the power dissipated by the resistor

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

The resistance of an electrical toaster has a temperature dependence given by

R (T) = R_{0} [1 + α (T - T_{0})]

in its range of operation. At

T_{0} = 300 K, R = 100 Ω and a t T = 500 K, R = 120 Ω

. The toaster is connected to a voltage source at

200 V

and its temperature is raised at a constant rate from

300 to 500 K

30 s

. The total work done in raising the temperature is :

Note: This question was awarded as the bonus since all options were incorrect in the exam.

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

For safety, the fuse wire used in the mains for household supply of electricity must be made of metal having

HARD

Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

Heater of an electric kettle is made of a wire of length

L

and diameter

d

. It takes

4

minutes to raise the temperature of

0.5 kg

water by

40 K

. This heater is replaced by a new heater having two wires of the same material, each of length

L

and diameter

2 d

. The way these wires are connected is given in the options. How much time in minutes will it take to raise the temperature of the same amount of water by

40 K

MEDIUM

Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

The resistor

R_{1} = 3 Ω

and

R_{2} = 1 Ω

are connected in parallel to a

20 V

battery. Find the heat developed in the resistor

R_{1}

in one minute

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

The energy dissipated by a resistor is

10 mJ

1 s

, when an electric current of

2 mA

flows through it. The resistance is ________

Ω

. (Round off to the Nearest Integer)

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

A light bull is rated at

110 W

for a

220 V

supply. The resistance of the bulb is

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

In which of the following devices, the eddy current effect is not used?

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Physics>Electricity and Magnetism>Current Electricity>Electrical Energy and Electrical Power

The charge flowing through a resistance

R

varies with time

t

Q = a t - b t^{2}

where

a

and

b

are positive constants. The total heat produced in

R

is:

Two metallic wires of the same material and same length have different diameters. If we connect them in series across a battery, the heat produced is H1, If we connect them in parallel to the same battery, the heat produced during the same time is H2. From the above, we infer that

Important Questions on Current Electricity

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