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 consumed using different electrical appliances, for which electricity bills are paid?
An electric bulb is rated at 220 V, 100 W. What is its resistance?
An electric bulb is connected to a 220 V power supply line. If the bulb draws a current of 0.5 A, calculate the power of the bulb.
An electric fan runs from the 230 V mains. The current flowing through it is 0.4 A. At what rate is electrical energy transferred by the fan?
The diagram below shows a circuit containing a lamp L, a voltmeter and an ammeter,. The voltmeter reading 3 V and the ammeter reading is 0.5 A.
What is the resistance of the lamp?
What is the power of the lamp?
List the names of three electrical gadgets used in your house. Write their power, voltage ratingand approximate time for which each one is used in a day. Hence find the electrical energyconsumed by each in a day.
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.
Two bulbs are rated 60 W, 220 V and 60 W, 110 V respectively. Calculate the ratio of their
resistances
An electric bulb, when connected across a power supply of 220 V, consumes a power of 60 W. If the supply drops to 180 V, what will be the power consumed? If the supply is suddenly increased to 240 V, what will be the power consumed?
The diagram above shows a circuit with the key k open. Calculate :
(i) the resistance of the circuit when the key k is open.
(ii) the current drawn from the cell when the key k is open.
(iii) the resistance of the circuit when the key k is closed.
(iv) the current drawn from the cell when the key k is closed.
An electric bulb of resistance 500 Ω draws current 0.4 A from the source. Calculate:
Why is heating coil wound in the form of a helix in electric stove?
An electric filament lamp is connected to a supply of voltage higher than the recommended value. Give reasons, why compared with a normal performance, the lamp emits a brighter light and its life is shortened.
Why does not the heating coil produce any visible light? in an electric stove.
What would happen and why, to an electric bulb when it is connected across a supply of voltage (i) lower (ii) higher than its proper rating?
How does the heat produced by die passage of current in a metallic wire depend on the current in the wire?
State (i) the S. I. unit, (ii) the household unit, of electrical energy. How are these units related?
An electric bulb is rated as 100W – 250V. What information does it convey? Calculate the resistance of its filament while glowing.
An electric bulb is rated as 100W – 250V. What information does it convey? Calculate the current through the filament of the bulb.
