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

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Important Questions on Electricity

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General Science>Physics>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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General Science>Physics>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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General Science>Physics>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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General Science>Physics>Electricity>Electrical Energy and Electrical Power

The power dissipated in the circuit shown in the figure is

30 W

. The value of

R

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General Science>Physics>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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General Science>Physics>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

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General Science>Physics>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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General Science>Physics>Electricity>Electrical Energy and Electrical Power

A light bulb of resistance $R = 16 Ω$ is attached in series with an infinite resistor network with identical resistances as shown below. A $10 V$ battery derives a current in the circuit. What should be the value of $r$ such that the bulb dissipates about $1 W$ of power?

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General Science>Physics>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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General Science>Physics>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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General Science>Physics>Electricity>Electrical Energy and Electrical Power

A current of

2 mA

was passed through an unknown resistor which dissipated a power of

4.4 W .

Dissipated power when an ideal power supply of

11 V

is connected across it is:

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General Science>Physics>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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General Science>Physics>Electricity>Electrical Energy and Electrical Power

Two electric bulbs, rated at

(25 W, 220 V)

and

(100 W, 220 V),

are connected in series across a

220 V

voltage source. If the

25 W

and

100 W

bulbs draw powers

P_{1}

and

P_{2}

respectively, then:

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General Science>Physics>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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General Science>Physics>Electricity>Electrical Energy and Electrical Power

A filament bulb

(500 W, 100 V)

is to be used in a

230 V

main supply. When a resistance,

R

is connected in series, it works perfectly and the bulb consumes

500 W

. The value of

R

HARD

General Science>Physics>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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General Science>Physics>Electricity>Electrical Energy and Electrical Power

A uniform metallic wire of length $L$ is mounted in two configurations. In configuration $1$ (triangle), it is an equilateral triangle and a voltage, $V$ is applied to corners $A$ and $B$ . In configuration $2$ (circle), it is bent in the form of a circle, and the potential $V$ is applied at diametrically opposite points $P$ and $Q$ . The ratio of the power dissipated is configuration $1$ to configuration $2$ is.

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General Science>Physics>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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General Science>Physics>Electricity>Electrical Energy and Electrical Power

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

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General Science>Physics>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:

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

Important Questions on Electricity

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