Advertisements
Advertisements
प्रश्न
State the S.I. units of electrical power and electrical energy.
(i) Define the household unit of electricity.
(ii) What is the voltage of the electricity that is generally supplied to a house?
Advertisements
उत्तर
The SI unit of electrical energy is joule.
The SI unit of electrical power is watt.
(i) Kilowatt-hour is the household unit of electrical energy. It is defined as the quantity of electrical energy consumed in 1 hour when the rate of consumption is 1000 watts, i.e. 1000 J/s.
(ii) A voltage of 220 volt is generally supplied to a house.
APPEARS IN
संबंधित प्रश्न
An electric heater of resistance 8 Ω takes a current of 15 A from the mains supply line. Calculate the rate at which heat is developed in the heater.
In a filament type light bulb, most of the electric power consumed appears as:
(a) visible light
(b) infra-red-rays
(c) ultraviolet rays
(d) fluorescent light
Distinguish between kilowatt and kilowatt-hour.
An electric bulb of resistance 500 Ω draws current 0.4 A from the source. Calculate:
- the power of bulb and
- the potential difference at its end.
Why is heating element wound on a long porcelain rod in a room heater.
The electric bulbs used these days have a coil-coiled filament. State its reason.
An Electric bulb is marked 100 W, 230 V. What how long would this lamp take to consume one unit of electricity?
The resistance of filament of an electric heater is 500 Ω It is operated at 200V for 1 hour daily. Calculate the current drawn by the heater and the energy consumed in kWh, by the heater in a month of 30 days.
A family uses 8 kW of power. Direct solar energy is incident on the horizontal surface at an average rate of 200 W per square meter. If 20% of this energy can be converted to useful electrical energy, how large an area is needed to supply 8 kW?
