Advertisements
Advertisements
Question
What changes in energy occur in an electric heater?
Advertisements
Solution
In an electric heater, electrical energy changes to heat energy.
RELATED QUESTIONS
The unit for expressing electric power is:
(a) volt
(b) joule
(c) coulomb
(d) watt
An electric kettle for use on a 230 V supply is rated 3000 W. For safe working, the cable connected to it should be able to carry at least:
(a) 2 A
(b) 5 A
(c) 10 A
(d) 15 A
Explain why, filament type electric bulbs are not power efficient.
Write an expression for the electrical power spent in flow of current through a conductor in terms of
(a) Resistance and potential difference, (b) current and resistance.
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
An electric bulb is rated 250 W, 230 V. Calculate:
- the energy consumed in one hour
- the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains.
What is the current in the circuit shown (Fig. )

Write the SI units for:
(a) Electric current
(b) Potential difference
(c) Charge.
In an electric radiator or room heater, state with reason, why the porcelain tube wound with a nichrome wire is placed between the pole and principal focus of the parabolic concave reflector.
