Advertisements
Advertisements
Question
How does the heat produced by die passage of current in a metallic wire depend on the current in the wire?
Advertisements
Solution
The heat produced is proportional to the square of current passed in the wire.
RELATED QUESTIONS
A 2 kWh heater, a 200 W TV and three 100 W lamps are all switched on from 6 p.m. to 10 p.m. What is the total cost at Rs 5.50 per kWh?
At a given time, a house is supplied with 100 A at 220 V. How many 75 W, 220 V light bulb could be switched on in the house at the same time (if they are all connected in parallel)?
State whether an electric heater will consume more electrical energy or less electrical energy per second when the length of its heating element is reduced. Give reasons for your answer.
A geyser is rated 1500 W, 250 V. This geyer is connected to 250 V mains. Calculate:
(i) the current drawn
(ii) the energy consumed in 50 hours, and
(iii) the cost of energy consumed at Rs. 4.20 per kWh
Define 1 kilowatt hour.
The diagram 31 shows a 3 terminal plug socket.
(i) What is the purpose of the terminal E?
(ii) To which part of the appliance is the terminal E connected?
(iii) To which wire L or N, is the fuse connected and why?
An electric current is passed through a metallic wire. The wire gets heated up. Give the reason. Is it possible to melt the wire by passing a heavy current?
Two lamps are rated 220V, 50W and the other rated 220V, 100W are connected in series with the mains of 220 V. Explain, why the 50W lamp glows more?
An electrical appliance is rated 1500 W, 250 V. This appliance is connected to 250 V mains. Calculate:
(i) the current drawn,
(ii) the electrical energy consumed in 60 hours,
(iii) the cost of electrical energy consumed at Rs. 2.50 per kWh.
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.
