Electromagnetic Waves Quiz - ICSE Class 12 Physics
Free practice quiz: Electromagnetic Waves (ICSE Class 12 Physics). 50 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
Play all 50 questions freeSample questions
Which of the following electromagnetic waves has the highest frequency?
- Infrared radiation
- Microwaves
- Gamma rays
- Ultraviolet radiation
Show answer
Answer: C. Gamma rays
The electromagnetic spectrum is ordered by frequency and wavelength. Gamma rays have the highest frequency and shortest wavelength, followed by X-rays, ultraviolet radiation, visible light, infrared radiation, microwaves, and radio waves.
When an electromagnetic wave passes from a vacuum into a medium, its speed:
- Increases
- Decreases
- Remains the same
- Becomes zero
Show answer
Answer: B. Decreases
The speed of an electromagnetic wave in a medium is given by v = c/n, where 'c' is the speed of light in a vacuum and 'n' is the refractive index of the medium. Since n is greater than 1 for all media, the speed decreases.
The energy of a photon of electromagnetic radiation is quantized, meaning it exists in discrete packets called:
- Waves
- Frequencies
- Quanta
- Photons
Show answer
Answer: D. Photons
According to quantum theory, electromagnetic radiation is emitted or absorbed in discrete packets of energy known as photons. The energy of each photon is given by E=hf.
The property of electromagnetic waves that allows them to be sorted by color is:
- Polarization
- Intensity
- Wavelength
- Amplitude
Show answer
Answer: C. Wavelength
Different colors of visible light correspond to different wavelengths. When white light is dispersed, these different wavelengths are separated.
The SI unit for frequency is:
- Second (s)
- Meter (m)
- Hertz (Hz)
- Watt (W)
Show answer
Answer: C. Hertz (Hz)
Hertz (Hz) is the SI unit of frequency, defined as one cycle per second.