Free Electromagnetic Waves MCQs with Answers
92 Electromagnetic Waves MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Electromagnetic waves consist of mutually perpendicular, oscillating electric and magnetic fields that also remain perpendicular to the direction of propagation. They travel through vacuum at the speed of light and include radio waves, microwaves, infrared, visible, ultraviolet, X-rays and gamma rays. Unlike mechanical waves, they do not require a material medium.
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92 questions · page 4 of 5
- A. speed of electromagnetic waves
- B. Frequency of light
- C. speed of light
- D. Frequency of electromagnetic waves
Explanation: Accelerating electromagnetic charges, such as electrons, radiate electromagnetic waves, which are a combination of electric and magnetic…
Correct answer: speed of light- A. 10 kHz
- B. 0.1 MHz
- C. 1 kHz
- D. 1000Hz
Explanation: Explanation:Frequency is measured in Hertz (Hz). Higher frequency means more cycles per second.1 kHz = 1000 Hz, 1 MHz = 1,000,000 Hz.0.1…
Correct answer: 0.1 MHz- A. Sonic
- B. Supersonic
- C. Hypersonic
- D. Ultrasonic
- E. infrasonic
Explanation: When an object is moving faster than the speed of sound in a medium, it is considered supersonic.
Correct answer: Supersonic- A. 1/√µ0ε0
- B. 1/2 µ0ε0
- C. 1/µ0ε0
- D. √µ0ε0
- E. µ0ε0
Explanation: Answer : AExplanation : As it is a numerical only one option is correct
Correct answer: 1/√µ0ε0- A. Motion of electric and magnetic fields
- B. Chargeless particles
- C. A static charge
- D. Heat
- E. None of the above
Explanation: Electromagnetic waves are the combination of electric and magnetic field waves produced by moving charges.The creation of all…
Correct answer: Motion of electric and magnetic fields- A. 7800 Å to 1500 Å
- B. 1Å to 100 Å
- C. 4000 Å to 8000 Å
- D. 8000 Å to 10,000 Å
Explanation: The range of wavelengths for visible light is 4000 Å to 8000 Å
Correct answer: 4000 Å to 8000 Å- A. X-rays
- B. Radio waves
- C. Infra red
- D. Visible light
Explanation: The wavelength of electromagnetic waves increases as you move from Gamma to Radio waves.
Correct answer: Radio waves- A. I only.
- B. III only.
- C. I and II.
- D. All of these
Explanation: I. light waves: Yes, as they are electromagnetic waves and the Doppler effect applies to them (e.g., in astronomy). * II.
Correct answer: All of these- A. be longer.
- B. be shorter
- C. become infinite.
- D. remain the same.
Explanation: * Doppler Effect Principle: The Doppler Effect describes the change in frequency or wavelength of a wave in relation to an observer who is…
Correct answer: be shorter70. Which of the following options shows the behaviour of X-rays when it passes through magneticfield?
- A. Option A:They are deflected
- B. Option B:They are absorbed
- C. Option C:They are accelerated
- D. Option D:They are unaffected
Explanation: X-rays are a form of electromagnetic radiation and, unlike charged particles, are not influenced by magnetic fields.
Correct answer: Option D:They are unaffected- A. parallel to the electric field only
- B. perpendicular to the magnetic field only.
- C. parallel to both electric and magnetic fields.
- D. perpendicular to both electric and magnetic fields.
Explanation: The correct answer is Option D: perpendicular to both electric and magnetic fields.
Correct answer: perpendicular to both electric and magnetic fields.- A. Velocity
- B. Intensity
- C. Amplitude
- D. Acceleration
Explanation: In frequency modulation (FM), the frequency of the carrier wave is varied in proportion to the amplitude of the modulating signal while…
Correct answer: Intensity- A. Mechanical waves
- B. Sound waves
- C. Tidal waves
- D. Electromagnetic waves
Explanation: Waves that do not require any medium for their propagation are called electromagnetic waves.
Correct answer: Electromagnetic waves- A. Electric field
- B. Magnetic field
- C. Both Options A and B are correct
- D. None of these options is correct
Explanation: Remember that x-rays and gamma rays cannot be deflected by electric and magnetic fields.
Correct answer: None of these options is correct- A. UV
- B. IR
- C. X-rays
- D. Gamma-rays
Explanation: The UV light from Sun is converted to IR as it interacts with the Earth's surface and this IR is then trapped by green house gases such as…
Correct answer: IR- A. 3 x 10^5 ms-1
- B. 3 x 10^3 ms-1
- C. 3 x 10^6 ms-1
- D. 3 x 10^8 ms-1
Explanation: Explanation:The speed of light, radio waves, and microwaves in the vaccum is the same, which is approximately 3 × 108 m/s.
Correct answer: 3 x 10^8 ms-1- A. 2.45 GHz
- B. 2452 Hz
- C. 2456 Hz
- D. 2455 Hz
Explanation: The electromagnetic waves used in a microwave oven have a frequency of 2.45 x 10° Hz.
Correct answer: 2.45 GHz- A. Gamma rays
- B. UV
- C. Microwave
- D. X-rays
Explanation: In the given electromagnetic spectrum it can be seen that wavelength increases from gamma rays towards radio waves and frequency…
Correct answer: Microwave- A. Modulated waves
- B. Carrier waves
- C. Standing waves
- D. Rectified waves
Explanation: Such waveforms are used in modulation. Modulation is the process of converting data into radio waves by adding information to an…
Correct answer: Carrier waves- A. Alpha rays
- B. X_rays
- C. Cosmic rays
- D. Beta rays
Explanation: Cosmic rays are high-energy particles that come from outside our solar system.
Correct answer: Cosmic rays