The principle of a microwave oven is MCQ with Answer and Explanation

The principle of a microwave oven is
A. Infrared radiation
B. Induction heating
C. Convection heating
D. Dielectric heating
Answer: Option D
Solution (By JKSSB Mock Tests)
Microwaves (2.45 GHz) are absorbed by water, fat, sugar molecules, causing them to rotate and generate heat through dielectric heating. Not induction (metal). Not conventional convection.

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Practice More Physics Questions

Question #1
In which of the following scenarios is the work done physically zero?
A. All of the above.
B. A satellite moving in a circular orbit around the Earth.
C. A person pushing a heavy wall that does not move.
D. A person carrying a heavy load on his head and walking on a horizontal road.

Correct Answer: Option A


Explanation:
Work (W) = F × d × cos(θ). In scenario A, displacement (d) is zero. In scenario B, the applied force (upward) is perpendicular to the displacement (horizontal), so cos(90°) = 0. In scenario C, the centripetal force (gravity) is perpendicular to the satellite's instantaneous direction of motion, so work done is zero. All cases yield zero work.

This question belongs to: Science Physics
Question #2
The odometer in a vehicle measures
A. Distance travelled
B. Engine RPM
C. Fuel consumption
D. Speed

Correct Answer: Option A


Explanation:
Odometer records cumulative distance. Speedometer shows instantaneous speed.

This question belongs to: Science Physics
Question #3
The force between two charges is 10 N in vacuum. If a dielectric of constant 5 is inserted, force becomes
A. 2 N
B. 0.5 N
C. 10 N
D. 50 N

Correct Answer: Option A


Explanation:
F_medium = F_vacuum / K = 10/5 = 2 N.

This question belongs to: Science Physics