Assertion : Fuse wire must have high resistance and low melting point.
Reason : Fuse is used for small current flow only.

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion
C. If assertion is true but reason is false
D. If the assertion and reason both are false.

Answer

C

Explanation

Assertion is true but reason is false. Fuse wire must have high resistance because in series current remains same, therefore according to Joule.s law `H = (i^(2) Rt)/4.2`,heat produced is high if R is high. The melting point must be low so that wire may melt with increase in temperature.
As the current flows equal to the maximum safe value through the fuse wire, it heats up, melts and breaks the circuit.