Physics

Electromagnetic Waves and Spectrum

670 Questions

Electromagnetic waves and spectrum questions test a candidate's understanding of radiation frequencies, wavelengths, and the properties of different rays like infrared, ultraviolet, and visible light. Concepts also cover practical applications in astronomy and the fundamental speed of light calculations. This physics topic appears regularly in general science sections of major competitive examinations.

UV rays propertiesElectromagnetic radiation frequencyWavelength identificationSpeed of light calculationsBlack body radiation

Electromagnetic Waves and Spectrum Questions

Multiple choice

What is the de Broglie wavelength of a particle?

  1. $\frac{h}{p}$
  2. $\frac{p}{h}$
  3. $\frac{E}{p}$
  4. $\frac{p}{E}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The de Broglie wavelength, named after Louis de Broglie, is given by the equation $\frac{h}{p}$, where $h$ is Planck's constant and $p$ is the momentum of the particle.

Multiple choice

What is the de Broglie wavelength of a photon?

  1. $\frac{h}{p}$
  2. $\frac{p}{h}$
  3. $\frac{E}{p}$
  4. $\frac{p}{E}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The de Broglie wavelength of a photon is given by the equation $\frac{h}{p}$, where $h$ is Planck's constant and $p$ is the momentum of the photon.

Multiple choice

The Wien displacement law states that the wavelength of the peak emission of a blackbody is inversely proportional to its absolute temperature. Which of the following objects emits light with the shortest wavelength?

  1. A red-hot iron bar

  2. A blue flame

  3. A white-hot light bulb

  4. A piece of ice
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A blue flame emits light with the shortest wavelength among the given objects, due to its higher temperature.

Multiple choice

Which laser wavelength is commonly used for laser skin resurfacing?

  1. 1064 nm

  2. 532 nm

  3. 800 nm

  4. 1550 nm
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

1064 nm wavelength is commonly used for laser skin resurfacing due to its deep penetration and minimal absorption by melanin, making it suitable for treating a variety of skin conditions.

Multiple choice

Which laser wavelength is commonly used for laser hair removal?

  1. 755 nm

  2. 1064 nm

  3. 532 nm

  4. 800 nm
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

800 nm wavelength is commonly used for laser hair removal due to its ability to target melanin in hair follicles while minimizing damage to surrounding skin.

Multiple choice

Which laser wavelength is commonly used for laser prostate surgery?

  1. 532 nm

  2. 800 nm

  3. 1064 nm

  4. 1550 nm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

1064 nm wavelength is commonly used for laser prostate surgery due to its ability to penetrate tissue deeply and its minimal absorption by blood, allowing for precise tissue ablation.

Multiple choice

What is the approximate wavelength range of solar ultraviolet radiation studied by Indian scientists?

  1. 10 nm - 100 nm

  2. 100 nm - 200 nm

  3. 200 nm - 300 nm

  4. 300 nm - 400 nm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Indian scientists primarily focus on the wavelength range of 200 nm - 300 nm, which corresponds to the ultraviolet-C (UVC) and ultraviolet-B (UVB) regions of the solar spectrum.

Multiple choice

What is the speed of light in a vacuum?

  1. 3 x 10^8 m/s

  2. 3 x 10^9 m/s

  3. 3 x 10^10 m/s

  4. 3 x 10^11 m/s
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The speed of light in a vacuum is approximately 3 x 10^8 meters per second, which is one of the fundamental constants of the universe.

Multiple choice

What is the relationship between the frequency and wavelength of light?

  1. Frequency is directly proportional to wavelength

  2. Frequency is inversely proportional to wavelength

  3. Frequency is independent of wavelength

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The frequency and wavelength of light are inversely proportional, meaning that as the frequency increases, the wavelength decreases, and vice versa.

Multiple choice

Which of the following is a type of electromagnetic wave?

  1. radio waves

  2. microwaves

  3. infrared waves

  4. ultraviolet waves
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

Radio waves, microwaves, infrared waves, and ultraviolet waves are all types of electromagnetic waves.

Multiple choice

The speed of light in a vacuum is approximately:

  1. 3 x 10^8 m/s

  2. 3 x 10^9 m/s

  3. 3 x 10^10 m/s

  4. 3 x 10^11 m/s
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The speed of light in a vacuum is approximately 3 x 10^8 m/s.

Multiple choice

What is the sensitivity of the IndIGO-A detector?

  1. 10^-23 m/√Hz

  2. 10^-24 m/√Hz

  3. 10^-25 m/√Hz

  4. 10^-26 m/√Hz
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sensitivity of the IndIGO-A detector is 10^-24 m/√Hz.

Multiple choice

What is the expected range of the IndIGO-A detector?

  1. 100 Mpc

  2. 200 Mpc

  3. 300 Mpc

  4. 400 Mpc
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The expected range of the IndIGO-A detector is 300 Mpc.

Multiple choice

What type of electromagnetic radiation has wavelengths longer than visible light but shorter than microwaves?

  1. Ultraviolet

  2. Infrared

  3. X-ray

  4. Gamma ray
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Infrared radiation has wavelengths longer than visible light but shorter than microwaves.

Multiple choice

What is the approximate wavelength range of infrared radiation?

  1. 0.4 - 0.7 μm

  2. 0.7 - 1.0 μm

  3. 1.0 - 10 μm

  4. 10 - 100 μm
Reveal answer Fill a bubble to check yourself
Correct answer
Explanation

Infrared radiation typically has wavelengths ranging from 1.0 to 100 μm.