Assertion (A): Generally an alloy of lead and tin is used as a material of the fuse wire. Reason (R): Alloy of lead and tin has a higher melting point than copper and aluminium.
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- B(A) is true, but (R) is false
- C(A) is false, but (R) is true
- DBoth (A) and (R) are true, but (R) is not the correct explanation of (A)
Show answer and explanation
Correct answer: (b) (A) is true, but (R) is false
Explanation
(A) is true: fuse wire is made of a low-melting tin–lead alloy so it melts and breaks the circuit on excess current.
(R) is false: tin–lead solder melts at only ~183–230 °C, far below aluminium (~660 °C) and copper (~1085 °C).
The low melting point is precisely why it suits a fuse, so (R) is incorrect.