JEE Physics · 80 questions. Try each one, then check the answer and solution.
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Q61.AI-generated practiceSingle-correct MCQEasy
In a plane electromagnetic wave, the average energy density associated with the electric field compared with that of the magnetic field is:
Q62.AI-generated practiceSingle-correct MCQEasy
The intensity of an electromagnetic wave is related to its average energy density u by:
Q63.AI-generated practiceSingle-correct MCQMedium
A plane electromagnetic wave in vacuum has an electric field amplitude of 100 V/m. Its intensity is about (ε0 = 8.85 × 10-12 C2 N-1 m-2, c = 3 × 108 m/s):
Q64.AI-generated practiceSingle-correct MCQMedium
Sunlight reaching the Earth has an intensity of about 1.4 kW/m2. The amplitude of its electric field is about (ε0 = 8.85 × 10-12 C2 N-1 m-2, c = 3 × 108 m/s):
Q65.AI-generated practiceSingle-correct MCQMedium
A small source radiates 100 W of electromagnetic power uniformly in all directions. The intensity at a distance of 2 m is about:
Q66.AI-generated practiceSingle-correct MCQHard
Light of intensity 1.2 kW/m2 falls normally on a surface that absorbs it completely. The radiation pressure on the surface is (c = 3 × 108 m/s):
Q67.AI-generated practiceSingle-correct MCQHard
Light of intensity 1.2 kW/m2 falls normally on a perfectly reflecting mirror. The radiation pressure on the mirror is (c = 3 × 108 m/s):
Q68.AI-generated practiceSingle-correct MCQMedium
A surface completely absorbs 30 J of electromagnetic energy arriving normally. The momentum delivered to the surface is (c = 3 × 108 m/s):
Q69.AI-generated practiceSingle-correct MCQMedium
If the amplitude of the electric field of an electromagnetic wave is doubled, its intensity becomes:
Q70.AI-generated practiceSingle-correct MCQEasy
The energy carried by a plane electromagnetic wave flows in the direction of:
Q71.AI-generated practiceSingle-correct MCQHard
A plane electromagnetic wave has an intensity of 10 W/m2. The amplitude of its magnetic field is about (ε0 = 8.85 × 10-12 C2 N-1 m-2, c = 3 × 108 m/s):
Q72.AI-generated practiceSingle-correct MCQMedium
A laser beam of power 3 mW has a cross-sectional area of 1 mm2. Its intensity is:
Q73.AI-generated practiceSingle-correct MCQMedium
In an electromagnetic wave in vacuum, the ratio of the energy density of the electric field to that of the magnetic field at any instant is:
Q74.AI-generated practiceSingle-correct MCQEasy
The SI unit of intensity of an electromagnetic wave is:
Q75.AI-generated practiceNumerical valueEasy
A small source radiates 12.56 W uniformly in all directions. Find the intensity at a distance of 1 m in W/m2, to the nearest integer.
Q76.AI-generated practiceNumerical valueMedium
Sunlight of intensity 1.5 kW/m2 falls normally on a perfectly absorbing surface of area 2 m2. If the force exerted on the surface is x × 10-6 N, find x. (c = 3 × 108 m/s)
Q77.AI-generated practiceNumerical valueMedium
A plane electromagnetic wave in vacuum has an intensity of 13.3 W/m2. Find the amplitude of its electric field in V/m, to the nearest integer. (ε0 = 8.85 × 10-12 C2 N-1 m-2, c = 3 × 108 m/s)
Q78.AI-generated practiceNumerical valueHard
A light pulse carrying 6 J of energy falls normally on a perfectly reflecting mirror. If the momentum transferred to the mirror is x × 10-8 kg m/s, find x. (c = 3 × 108 m/s)
Q79.AI-generated practiceAssertion–ReasonMedium
Assertion (A): Electromagnetic waves exert a pressure on surfaces they fall on. Reason (R): Electromagnetic waves carry momentum.
Q80.AI-generated practiceAssertion–ReasonHard
Assertion (A): In an electromagnetic wave the energy density of the magnetic field is much smaller than that of the electric field. Reason (R): The amplitude of the magnetic field, B0 = E0/c, is numerically much smaller than E0.