Which component in an electrical circuit is specifically designed to melt and break the circuit in the event of an overload? MCQ with Answer and Explanation
Which component in an electrical circuit is specifically designed to melt and break the circuit in the event of an overload?
A. Switch
B. Capacitor
C. Resistor
D. Fuse
Answer: Option D
Solution (By JKSSB Mock Tests)
A fuse is an electrical safety device consisting of a wire made of an alloy with a low melting point. If the current exceeds a safe limit (due to a short circuit or overload), the Joules heating (I²Rt) causes the wire to melt instantly, breaking the circuit and preventing fire or damage to appliances.
Explanation:
An ammeter must have very low resistance so it does not alter the circuit current it is measuring. To convert a sensitive galvanometer into an ammeter, a very low resistance called a 'shunt' is connected in parallel to it. This diverts most of the current away from the delicate galvanometer coil while still allowing a proportional measurement.
Explanation:
J. J. Thomson discovered the electron in 1897 through his experiments with cathode ray tubes. He demonstrated that cathode rays were actually streams of negatively charged subatomic particles, much smaller than atoms. Rutherford is famous for discovering the nucleus (gold foil experiment), Chadwick discovered the neutron, and Bohr developed the planetary model of the atom.
Explanation:
F = m×a. New force F' = (2m)×(a/2) = m×a = F. So force remains unchanged. This is direct proportionality. Understand the relationship: doubling mass doubles force, halving acceleration halves it, net effect no change.
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