EASY

12th CBSE

IMPORTANT

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Two bulbs rated $25 W$ , $220 V$ and $100 W$ , $220 V$ are connected in series to a $440 V$ supply. What will happen if the two bulbs are connected in parallel to the same supply?

Important Questions on Current Electricity

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 18

A servo voltage stabilizer restricts the voltage output to

220 V

\pm 1 %

. If an electric bulb rated at

220 V

100 W

is connected to it, what will be the minimum and maximum power consumed by it?

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 19

A room is lighted by

200 W

124 V

incandescent lamps fed by a generator whose output voltage is

130 V

. The connecting wires from the generator to the user are made of aluminium wire of total length

150 m

and cross‐sectional area

15 {mm}^{2}

. How many such lamps can be installed? Specific resistance of aluminium

= 2.9 \times 10^{- 8} Ω m

MEDIUM

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 20

Two wires

A

and

B

of same material and mass, have their lengths in the ratio

1 : 2

. On connecting them, one at a time to the same source of emf, the rate of heat dissipation in

B

is found to be

5 W

. What is the rate of heat dissipation in

A

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 21

An electric heater and an electric bulb are rated

500 W

220 V

and

100 W

220 V

respectively. Both are connected in series to a

220 V

d.c. mains. Calculate the power consumed by the heater.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 21

An electric heater and an electric bulb are rated

500 W

220 V

and

100 W

220 V

respectively. Both are connected in series to a

220 V

d.c. mains. Calculate the power consumed by the electric bulb.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 22

The heater coil of an electric kettle is rated as

2000 W

200 V

. How much time will it take to heat one litre of water from

20 ° C

100 ° C

, assuming that entire electric energy liberated from the heater coil is utilized for heating water? Also calculate the resistance of the coil. Density of water is

1 g {cm}^{- 3}

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 23

An electric kettle was marked

500 W

230 V

and was found to raise

1 kg

of water at

15 ° C

to the boiling point in

15

minutes. Calculate the heat efficiency of the kettle.

EASY

12th CBSE

IMPORTANT

New Simplified Physics (Vol 1) For Class 12>Chapter 3 - Current Electricity>Problems For Practice>Q 24

30 V

storage battery is being charged by

120 V d . c

. supply. A resistor has been connected in series with the battery to limit the charging current to

15 A

. Find the rate at which energy is dissipated in the resistor. If the total heat produced could be made available for heating water, how long would it take to bring

1 kg

of water from

15 ° C

to the boiling point? Specific heat of water

1 cal g^{- 1} ° C^{- 1}

and

1 c a l = 4.2 J

Two bulbs rated 25 W, 220 V and 100 W, 220 V are connected in series to a 440 V supply. What will happen if the two bulbs are connected in parallel to the same supply?

Important Questions on Current Electricity

Learn and Prepare for any exam you want !

Two bulbs rated $25 W$ , $220 V$ and $100 W$ , $220 V$ are connected in series to a $440 V$ supply. What will happen if the two bulbs are connected in parallel to the same supply?