Advertisements
Advertisements
Question
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?
Advertisements
Solution
The metallic wire gets heated up on passing an electric current through it due to collisions of free electrons and energy is transferred to the positive ions which begin to vibrate more violently, causing to produce heat. It is possible to melt the wire by passing a heavy current. The wire will melt when its temperature due to heating reaches its melting point.
RELATED QUESTIONS
Define Electric power.
1 kWh = ________ J
Name the quantity whose unit is kilowatt?
How many joules are there in one kilowatt-hour?
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 the S.I. unit of electrical power.
A bulb of 40 W is used for 12.5 h each day for 30 days. Calculate the electrical energy consumed.
The diagram below shows a magnetic kept just below the conductor AB which is kept in North South direction.
(i) In which direction will the needle deflect when the key is closed ?
(ii) Why is the deflection produced ?
(iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB ?
(iv) Name one device which works on this principle.
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?
Give two precautious that you would take while putting off an electric switch.
