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

State the S.I. units of electrical power.

Define the term kilowatt - hour and state its value in S.I. unit.

1 kWh = `(1 "volt" xx 1 "ampere" xx "_________")/1000`

Complete the following:

1 kWh = _________ J

An electric bulb is marked '100 W, 250 V'. What information does this convey?

Calculate the current through a 60 W lamp rated 250 V. If the line voltage falls to 200 V, how is 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.

1. What is its resistance?
2. 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 750 W, 230 V. Calculate the electrical energy consumed by the press in 16 hours.

A bulb marked 12 V, 24 W operates on a 12 V battery for 20 minutes. Calculate:

1. The current flowing through it, and
2. 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.

An electric bulb is rated 250 W, 230 V. 

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

Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply. Calculate :

The total current taken from the supply

Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply. The resistance of each heater

Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply of the energy supplied in kWh to the three heaters in 5 hours.

A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:

The total energy supplied by the battery in 10 minutes

A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:

The resistance of the bulb

A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:

The energy dissipated in the bulb in 10 minutes.

A battery of e.m.f. 15 V and internal resistance 2 Ω   is connected to two resistors of resistances 4 ohm and 6 ohm joined (a) in series. Find in each case the electrical energy spent per minute in 6 Ω resistor.