An electric iron rated 750 W is operated for 2 hours/day. How much energy is consumed by the electric iron for 30 days?
What is the meaning of the symbol kWh? Which quantity does it represent?
Which uses more energy: a 250 W TV set in 1 hour or a 1200 W toaster in 10 minutes?
The commercial unit of energy is :
(a) watt
(b) watt-hour
(c) kilowatt-hour
(d) kilo-joule
Explain why, filament type electric bulbs are not power efficient.
Calculate the resistance of an electric bulb which allows a 10 A current when connected to a 220 V power source.
A resistor of resistance R is connected to an ideal battery. If the value of R is decreased, the power dissipated in the resistor will ______________ .
What is electric power? State and define its S.I. unit.
Why is heating coil wound in the form of a helix in electric stove?
The electric bulbs used these days have a coil-coiled filament. State its reason.
Why does not the heating coil produce any visible light? in an electric stove.
Give two precautious that you would take while putting off an electric switch.
A family uses a light bulb of 100W, a fan of 100W, and a heater of 1000W, each for 8 hours a day. If the cost of electricity is Rs. 2 per unit, what is the expenditure to the family per day, on electricity?
Out of the three fuses with current ratings 5A, 10A, 15A, which one is to be connected in a geyser circuit marked 3 kW, 220V? Give reason for your answer.
Two resistances R1 = 4Ω and R2 = 6Ω are connected in series. The combination is connected with a battery of e.m.f. 6V and negligible resistance. Calculate:
(i) the heat produced per minute in each resistor,
(ii) the power supplied by the battery.
Find the cost of operating an electric toaster for two hours if it draws 8 A current on a 110 volt circuit. The cost of electrical energy is Rs. 2.50 per kWh.
If a heater coil rated lkW, 220 V is connected in series with an electric bulb of 100 W, 220 V and are supplied 200V, power consumed by the bulb in this circuit is ______.
