Physics

Electromagnetic Waves and Spectrum

659 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 relationship between frequency and wavelength?

  1. Frequency is directly proportional to wavelength

  2. Frequency is inversely proportional to wavelength

  3. Frequency is independent of wavelength

  4. Frequency is proportional to the square of wavelength
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Frequency and wavelength are related by the equation (f = c/\lambda), where f is frequency, c is the speed of light, and \lambda\ is wavelength. This means that frequency is inversely proportional to wavelength, as long as the speed of light remains constant.

Multiple choice

Which of the following is NOT a type of electromagnetic radiation?

  1. X-rays

  2. Gamma rays

  3. Ultraviolet light

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

Sound waves are mechanical waves and not electromagnetic radiation.

Multiple choice

Which of the following is NOT a type of electromagnetic radiation studied by astrophysicists?

  1. Visible light

  2. X-rays

  3. Gamma rays

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

Sound waves are not a type of electromagnetic radiation, and therefore are not studied by astrophysicists.

Multiple choice

Which of these colors has the shortest wavelength?

  1. Red

  2. Green

  3. Blue

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

The visible spectrum of light consists of colors with varying wavelengths. Violet light has the shortest wavelength, followed by blue, green, yellow, orange, and red.

Multiple choice

The speed of light in a vacuum is approximately:

  1. 3 × 10^8 m/s

  2. 9 × 10^8 m/s

  3. 12 × 10^8 m/s

  4. 15 × 10^8 m/s
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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

Multiple choice

Which of the following is NOT a type of electromagnetic radiation?

  1. Gamma Rays

  2. X-Rays

  3. Ultraviolet Rays

  4. Infrared Rays
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Infrared rays are not a type of electromagnetic radiation like gamma rays, X-rays, and ultraviolet rays.

Multiple choice

What is the speed of light in a vacuum?

  1. 300,000 kilometers per second

  2. 299,792,458 meters per second

  3. 186,282 miles per second

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The speed of light in a vacuum is approximately 300,000 kilometers per second, 299,792,458 meters per second, and 186,282 miles per second.

Multiple choice

The Wien displacement law states that the wavelength of maximum emission from a black body is inversely proportional to:

  1. The absolute temperature

  2. The pressure

  3. The volume

  4. The number of molecules
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Wien displacement law states that the wavelength of maximum emission from a black body is inversely proportional to the absolute temperature.

Multiple choice

What is the relationship between frequency and wavelength?

  1. They are inversely proportional

  2. They are directly proportional

  3. They are independent of each other

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

Frequency and wavelength are inversely proportional, meaning that as one increases, the other decreases. This relationship is expressed by the equation (v = f \lambda), where (v) is the wave velocity, (f) is the frequency, and (\lambda) is the wavelength.

Multiple choice

Which of the following is an example of an electromagnetic wave?

  1. Sound waves

  2. Ocean waves

  3. Light waves

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

Electromagnetic waves are waves that do not require a medium to propagate. Light waves are an example of electromagnetic waves.

Multiple choice

Which electromagnetic wave has the longest wavelength?

  1. Radio waves

  2. Microwaves

  3. Infrared radiation

  4. Ultraviolet radiation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Radio waves have the longest wavelength among the electromagnetic waves, ranging from a few centimeters to thousands of kilometers.

Multiple choice

Which electromagnetic wave has the highest frequency?

  1. Gamma rays

  2. X-rays

  3. Ultraviolet radiation

  4. Visible light
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gamma rays have the highest frequency and energy among the electromagnetic waves, typically originating from radioactive decay or nuclear reactions.

Multiple choice

Which of the following is NOT a type of electromagnetic radiation?

  1. Gamma rays

  2. X-rays

  3. Ultraviolet radiation

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

Sound waves are mechanical waves, not electromagnetic waves.

Multiple choice

The wavelength of electromagnetic radiation is inversely proportional to its:

  1. Frequency

  2. Energy

  3. Amplitude

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

The relationship between wavelength and frequency is given by the equation (c = \lambda f), where (c) is the speed of light, (\lambda) is the wavelength, and (f) is the frequency.