Tag: the electromagnetic spectrum

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Questions Related to the electromagnetic spectrum

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Name the seven prominent colours of the white light spectrum in order of their increasing frequencies

  1. Violet, Indigo, Blue, Green, Yellow, Orange, Red

  2. Red, Orange, Yellow, Green, Blue, Indigo, Violet

  3. Red, Orange, Violet, Yellow, Green, Blue, Indigo

  4. Orange, Yellow, Green, Red, Blue, Indigo, Violet
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The range of frequencies from red to violet is 430-790 THz.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

An electromagnetic wave has a frequency of $500MHz$ and a wavelength of $60cm$. Calculate the velocity of the wave.

  1. $3\times 10^8kms^{-1}$
  2. $3\times 10^8cms^{-1}$
  3. $3\times 10^{-8}ms^{-1}$
  4. $3\times 10^8ms^{-1}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The formula for velocity, when given wavelength and the frequency of the wave, is written as: $v=f\lambda $.
In this formula, $f$ represents frequency, $v$ represents the velocity of the wave, and $\lambda $ represents the wavelength of the wave.  
Here, the frequency of the wave is $500 MHz = 500000000 Hz$  and the wavelength is $60 cm = 0.6 m$
Hence, the velocity of the wave is $3\times { 10 }^{ 8 }m/s$.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Name the radiations of wavelength just longer than $8\times 10^{-7}m$.

  1. infrared

  2. ultrared

  3. infraviolet

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

In the order of increasing wavelength, the waves are Gamma rays ($< 1 nm$), X-rays ($1-10 nm$), infrared rays ($700-{ 10 }^{ 5 }nm$), micro waves (${ 10 }^{ 5 }-{ 10 }^{ 8 }nm$), radio waves (${ >10 }^{ 8 }nm$).
Hence, the radiations of wavelength just longer than ${ 8\times 10 }^{ -7 }m$ is Infrared.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Fraunhofer spectral lines are called:

  1. Line absorption spectra

  2. Line emission spectra

  3. continuous spectra

  4. Continuous emission spectra
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fraunhofer spectral lines are also called line absorption spectra. They are a set of spectral lines. The lines were originally observed as dark features (absorption lines) in the optical spectrum of the Sun.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Which of the following solar radiations pass through the atmosphere of earth:
X-rays, ultraviolet rays, visible light rays, infrared radiation.

  1. X-Ray

  2. Ultraviolet

  3. Visible

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

Generally, three types of radiation come from the sun to Earth, they are, ultraviolet radiation, visible light, and,  infrared radiation. Out of these three radiations, ultraviolet radiation is prevented by the ozone layer and visible light and high-frequency infrared radiation reach to earth, because they can pass through the atmosphere of the Earth.

Multiple choice physics spectra the electromagnetic spectrum electromagnetic spectrum electromagnetic waves

Radiations used to get relief from bodyaches are:

  1. I.R. radiations

  2. U.V. radiations

  3. visible radiations

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Infrared radiations are used as a part of thermal therapy. Thermal therapy is widely used for increasing the extensibility of the collagen, to decrease the joint stiffness, to relieve the muscle spasms, to increase the flow of the blood.