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.
Last updated
92 questions · page 5 of 5
- A. Stationary charges
- B. Charges moving with uniform speed
- C. Accelerating charges
- D. All of the above
Explanation: Electromagnetic waves are produced when charges undergo acceleration. Acceleration of charges creates changing electric and magnetic…
Correct answer: Accelerating charges- A. rectification
- B. amplification
- C. modulation
- D. magnification
Explanation: Modulation is the process of combining low-frequency signals with high-frequency carrier waves to convert data into radio waves.
Correct answer: modulation- A. 1x10
- B. 3.0 x 10^7
- C. 1x10¹0
- D. 1 x 10^13
Explanation: We know that v = f λ v --- = f λ (placing values) 3 × 10⁸ f = ------------------ 3 × 10⁻³ × 10⁻² f = 1 × 10¹³
Correct answer: 1 x 10^13- A. x rays > i.r. > u.v. > visible
- B. x rays > u.v. > visible > i.r.
- C. u.v. > x rays > visible > i.r.
- D. i.r. > visible > x rays > u.v.
Explanation: In the electromagnetic spectrum, the energy of photons is inversely proportional to their wavelength.
Correct answer: x rays > u.v. > visible > i.r.- A. Parallel
- B. Anti-parallel
- C. Perpendicular
- D. None of the above
Explanation: In electromagnetic waves, the electric and magnetic fields are oriented perpendicular to each other and to the direction of wave…
Correct answer: Perpendicular- A. Speed
- B. Wavelength
- C. Frequency
- D. All of the above
Explanation: Electromagnetic waves travel at a constant speed of approximately 3 × 10^8 m/s in a vacuum.
Correct answer: Speed- A. Gamma rays, ultraviolet rays, radio waves
- B. Gamma rays, visible radiation, ultraviolet rays
- C. Microwaves, ultraviolet rays, X-rays
- D. Radio waves, visible radiation, infrared radiation
Explanation: The electromagnetic spectrum is as such as wavelength decreases frequency increases, therefore the correct answer would be C ,as the…
Correct answer: Microwaves, ultraviolet rays, X-rays- A. Speed
- B. Energy
- C. Frequency
- D. Wavelength
Explanation: All electromagnetic radiations such as microwave, gamma rays or radio waves travel with a speed of light in a vacuum which is equal to 3.0…
Correct answer: Speed- A. An electric field
- B. Magnetic field
- C. Both A and B
- D. None of the above
Explanation: Faraday's law of electromagnetic induction states that a changing electric flux will result in the induction of a magnetic field.
Correct answer: Both A and B- A. Sound
- B. Supersonic
- C. Ultrasonic
- D. Light
Explanation: The correct answer is that the signal from a remote control travels at the speed of light.
Correct answer: Light- A. X-rays
- B. Gamma rays
- C. Microwaves
- D. Ultraviolet rays
Explanation: Gamma rays have the smallest wavelength of all electromagnetic waves, making them the highest in energy.
Correct answer: Gamma rays- A. An electric field only
- B. A magnetic field only
- C. Electromagnetic radiation only
- D. All of the above
Explanation: Accelerating charges produce changing electric and magnetic fields. Changing electric fields produce magnetic fields and changing magnetic…
Correct answer: All of the above