MCQ on Electromagnetic Spectrum

The whole distribution of electromagnetic radiation as per frequency or wavelength is referred to as the electromagnetic spectrum. In a vacuum, all electromagnetic waves travel at the speed of light, but at a variety of frequencies, wavelengths and photon energies. The electromagnetic spectrum encompasses all electromagnetic radiation and is divided into several subranges or sections, such as visible light and ultraviolet radiation. The various parts have distinct names due to changes in the behaviour of the corresponding waves in terms of emission, transmission and absorption, as well as their diverse practical uses.

1. The energy of discrete particles can be calculated using

a) Photons
b) Protoplasm
c) Electrons
d) Neutrons

Answer: Correct option will be: (a) Photons

Reason: In the case of an electromagnetic wave, photons serve as constituent particles. These have particular features, such as energy and momentum, that allow them to convey it to the wave and aid in categorization.

2. Which of the following has the greatest wavelengths?

a) X- rays
b) Cosmic rays
c) Radio waves
d) Gamma rays

Answer: Correct option will be: (c) Radio waves

3. In the case of remote sensing, which of the following waves is not used?

a) X rays
b) Visible ray
c) Thermal IR
d) Radio waves

Answer: Correct option will be: (a) X- rays

Reason: The atmosphere absorbs gamma, X-rays, and UV rays, preventing the sensor on the satellite from taking use of the services given by these wavelengths, which likewise have a very short wavelength.

4. Gamma rays have a wavelength of around:

a) 0
b) >0.03nm
c) <0.03nm
d) =0.03nm

Answer: Correct option will be: (c) <0.03nm

5. In the event of remote sensing, which of the waves below can be used?

a) X rays
b) Visible rays
c) UV rays
d) Gamma rays

Answer: Correct option will be: (b) Visible rays

Reason: The electromagnetic spectrum is divided into several categories, some of which are absorbed by the atmosphere and the majority of which are employed in remote sensing, such as visible rays, infrared rays, radar waves, and radio waves.

6. What is the wavelength of light that gets reflected back by the earth’s surface that was absorbed by the sun?

a) 0.5m
b) 0.5μm
c) 0.5cm
d) 0.5dm

Answer: Correct option will be: (b)0.5μm.

Reason: In general, the sun’s radiation is dispersed over the earth in such a way that the total amount of radiation is helpful. However, some of this gets reflected back at a distance of 0.5 micrometres, which is very short.

7. what is the phase difference between the electric field and magnetic field vectors in electromagnetic waves?

a) 0
b) π/4
c) π/2
d) π

Answer: Correct option will be: (a) 0.

8. Which of them has the shortest wavelength?

a) Blue light
b) IR
c) Microwaves
d) γ rays

Answer: Correct option will be: (d)γ rays

Reason: Among electromagnetic waves, -rays have the highest frequency and thus the shortest wavelength.

9. According to Maxwell’s theory, a changing electric field causes:

a) Electric field
b) Induced Electromotive force
c) Magnetic field
d) Magnetic dipole

Answer: Correct option will be: (c) Magnetic field

10. If E and B are the electric and magnetic field vectors of electromagnetic waves, then the em wave propagation direction is:

a) EB
b) BE
c) EB
d) BE

Answer: Correct option will be: (c) Eb)

11. The most efficient condition for a microwave to overheat a food item that contains water molecules is:

a) The microwaves’ frequency must be the same as the resonance frequencies of the molecules of water.
b) The inherent frequency of water molecules has no relation to the frequency of microwaves.
c) Because microwaves are heat waves, they always generate heat.
d) In a microwave oven, infrared radiation produces heat.

Answer: Correct option will be: (a) The microwaves’ frequency must be the same as the resonance frequencies of the molecules of water.

Reason: When the frequency of the microwave matches the frequency of the water molecules, this is referred to as a resonant state. Water molecules receive the most energy as their K.E. energy.

12. In medicine, which of the mentioned electromagnetic waves is utilised to kill cancer cells?

a) Infrared (IR) rays
b) Visible rays
c) Ultraviolet rays
d) Gamma rays

Answer: Correct option will be: (d) Gamma rays.

13. Choose the electromagnetic wave that is the most dangerous to humans.

a) Radio waves
b) UV rays
c) Microwaves
d) IR

Answer: Correct option will be: (b) UV rays

Reason: In significant doses, ultraviolet (UV) radiation is extremely damaging to humans. The ozone layer in the atmosphere absorbs these photons of solar radiation when they reach the planet. UV rays are emitted by particular lamps, such as mercury and arc lamps, as well as extremely hot substances, such as the sun.

14. Which of the mentioned waves is an electromagnetic wave?

a) α-rays
b) Ultrasonic waves
c) γ-rays
d) β-rays

Answer: Correct option will be: (c) γ-rays

15. What are the two colours that emerge from Prism’s two extreme ends?

a) Blue and Green
b) Yellow and Orange
c) Red and Orange
d) Violet and Red

Answer: Correct option will be: (d) Violet and Red

Reason: Because violet has a shorter wavelength than other colours, it bends the greatest, whereas red bends the least and is seen at the end of the prism opposite the base. As a result, Option d is right.

16. In vacuum, all electromagnetic spectrum components have the same:

a) Frequency
b) Wavelength
c) Velocity
d) Energy

Answer: Correct option will be: (c) Velocity

17. Which of the given waves has the maximum penetrating power?

a) α-rays
b) β-rays
c) γ-rays
d) All of the mentioned

Answer: Correct option will be: (c) γ-rays

18. The term “heat radiation” refers to which of the following?

a) X- rays
b) Gamma rays
c) Microwaves
d) Infrared radiation

Answer: Correct option will be: (d) Infrared radiations

19. Which of the following waves is used for investigating the solid structures?

a) X- rays
b) Gamma rays
c) Microwaves
d) Infrared radiations

Answer: Correct option will be: (a) X- rays.