Advertisements
Advertisements
Question
What is an ‘electric fuse’? State its two characteristics of electric fuse.
Advertisements
Solution
The electric fuse is a safety device in electric circuits, used to limit the current and thus it acts as a safeguard for the household circuit and any electric appliance connected in the circuit from being damaged. Its characteristics are:
(i) It has a low melting point (m.p.) of about 200°C and is usually made from an alloy of 50% tin and 50% lead.
(ii) It has a high resistance so that its temperature rises rapidly and soon exceeds its m.p. and thus breaks it, when current passing through it exceeds the permissible limits. In such a case it acts as a switch.
RELATED QUESTIONS
Explain the meaning of the student 'current rating of a fuse is 5A'.
Name the factors on which the heat produced in a wire depends when current is passed in it, and state how does it depend on the factors stated by you.
A fuse is a short piece of wire of high ______ and of material of low ______.
A fuse is connected in ______ with the ______ wire.
Why is the fuse wire fitted in a porcelain casing?
‘A fuse is rated 8 A’. can it be used with an electrical appliance of rating 5kW, 200V?
(i) Write one advantage of connecting electrical appliances in parallel combination.
(ii) What characteristics should a fuse wire have ?
(iii) Which wire in a power circuit is connected to the metallic body of the appliance ?
How does the length of a fuse wire depend on its current rating?
Name two safety devices which are connected to the live wire of a household electric circuit.
Why is it not advisable to use a piece of copper wire as fuse wire in an electric circuit?
