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 determines the rate at which energy is delivered by a current?
An electric kettle connected to the 230 V mains supply draws a current of 10 A. Calculate:
(a) the power of the kettle.
(b) the energy transferred in 1 minute.
Write the formula for electric power in terms of potential difference and current.
How many joules are there in one kilowatt-hour?
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
How many joules of electrical energy are transferred per second by a 6 V; 0.5 A lamp?
(a) 30 J/s
(b) 12 J/s
(c) 0.83 J/s
(d) 3 J/s
Explain why, filament type electric bulbs are not power efficient.
Why is an electric light bulb not filled with air? Explain why argon or nitrogen is filled in an electric bulb.
Two bulbs are rated 60 W, 220 V and 60 W, 110 V respectively. Calculate the ratio of their
resistances
An electric bulb marked 220 V, 100 W will get fused if it is made to consume 150 W or more. What voltage fluctuation will the bulb withstand?
Express watt hour and kilowatt hour in joule.
An electric heater is rated 220 V, 550 W. Electrical energy is also measured in kWh. What do you understand by a kilo-watt-hour?
Find the heat produced in joules when a current of 10 amperes flows through a connecting wire of resistance 2 × 10-2 ohms and heating element of resistance 250 ohms for 2 seconds.
The unit of e.m.f. of a cell is ____________.
1 kWh = ____________
A fuse is rated 5 A. Can it be used with a geyser rated 1540 W, 220 V Write Yes or No. Give supporting calculations to justify your answer.
