A fuse in an electrical circuit is designed to: MCQ with Answer and Explanation

A fuse in an electrical circuit is designed to:
A. Convert AC to DC
B. Increase current flow
C. Protect against overcurrent by melting
D. Store electrical energy
Answer: Option C
Solution (By JKSSB Mock Tests)
Fuse is a safety device with a wire that melts when current exceeds rated value, breaking the circuit and preventing damage from overcurrent/short circuits. It operates on Joule heating (I²R). Option A is opposite; C describes capacitor; D describes rectifier. Memory tip: 'Fuse = sacrificial overcurrent protector'. This practical application question tests knowledge of electrical safety devices, frequently examined in competitive exams. Always link fuse rating to circuit requirements: fuse current rating slightly above normal operating current.

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Practice More Physics Questions

Question #1
A brass rod of length 1 m at 0°C expands by 0.0019 m when heated to 100°C. Its linear expansion coefficient is
A. 1.9 × 10⁻⁵ /°C
B. 1.9 × 10⁻³ /°C
C. 1.9 × 10⁻⁴ /°C
D. 1.9 × 10⁻⁶ /°C

Correct Answer: Option A


Explanation:
ΔL = α L₀ ΔT => α = ΔL/(L₀ ΔT) = 0.0019/(1×100) = 1.9×10⁻⁵ /°C. Typical for brass. Unit is per °C. Always check ΔL/L per °C.

This question belongs to: Science Physics
Question #2
The change in momentum of a body is equal to
A. Impulse
B. Work
C. Force
D. Energy

Correct Answer: Option A


Explanation:
Impulse = F Δt = Δp (change in momentum). Derived from Newton's second law. Force is rate of change of momentum. Impulse-momentum theorem important for collisions.

This question belongs to: Science Physics
Question #3
In a p-type semiconductor, the majority charge carriers and the minority charge carriers are respectively:
A. Holes and Electrons
B. Ions and Holes
C. Protons and Electrons
D. Electrons and Holes

Correct Answer: Option A


Explanation:
A p-type semiconductor is created by doping a pure semiconductor (like Silicon) with a trivalent impurity (like Boron). This creates a deficiency of one electron, creating a 'hole'. These positive holes vastly outnumber the thermally generated free electrons. Thus, holes are the majority charge carriers, and electrons are the minority charge carriers.

This question belongs to: Science Physics