(English Medium) ICSE Class 10 - CISCE Question Bank Solutions

Distinguish between kilowatt and kilowatt-hour.

 1Kwh =`( 1  "volt "xx 1 am pere xx.............)/1000`

1kWh = …….. J

An electric bulb is rated ‘100 W, 250 V’. What information does this convey?

List the names of three electrical gadgets used in your house. Write their power, voltage rating and approximate time for which each one is used in a day. Hence, find the electrical energy consumed by each in a day.

Two lamps, one rated 220 V, 50 W and the other rated 220 V, 100 W, are connected in serieswith mains of 220 V. Explain why does the 50 W lamp consume more power

When a current I flows through a resistance R for time t, the electrical energy spent is given by:
(a) IRt (b) I²Rt (c) `IR^2t` (d) `I^2R ⁄t`

A current of 2 A is passed through a coil of resistance 75Ω for 2 minutes. (a) How much heat energy is produced? (b) How much charge is passed through the resistance?

Calculate the current through a 60 W lamp rated for 250 V. If the line voltage falls to 200 V, how is the power consumed by the bulb affected?

An electric bulb is rated ‘100 W, 250 V’. How much current will the bulb draw if connected to a 250 V supply?

An electric bulb is rated at 220 V, 100 W. (a) what is its resistance? (b) what safe current can be passed through it?

A bulb of 40 W is used for 12.5 h each day for 30 days. Calculate the electrical energy consumed.

An electric iron is rated at 750 W, 230 V. Calculate the electrical energy consumed by the iron in 16 hours .

An electrical appliance having a resistance of 200Ω is operated at 200 V. Calculate the energy consumed by the appliance in 5 minutes (i) in joules (ii) in kWh.

A bulb marked 12 V, 24 W operated on a 12 volt battery for 20 minutes. Calculate:
(i) the current flowing through it, and
(ii) the energy consumed

A current of 0.2 A flows through a wire whose ends are at a potential difference of 15 V.
calculate:
(i) the resistance of the wire and
(ii) the heat energy produced in 1 minute.

What is the resistance, under normal working conditions of a 240 V electric lamp rated at 60 W? If two such lamps are connected in series across a 240 V mains supply, explain why each one appears less bright.

State one difference between a musical note and a noise.

Two bulbs are rated 60 W, 220 V and 60 W, 110 V respectively. Calculate the ratio of their
resistances

An electric bulb is rated 250 W, 230 V. Calculate:

1. the energy consumed in one hour
2. the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains.