Tag: the nature of light

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Questions Related to the nature of light

Multiple choice physics option a: relativity the nature of light speed of light and optical density introduction to light

The velocity of electromagnetic radiation in a medium of permittivity ${\varepsilon} _{0}$ and permeability ${\mu} _{0}$ is given by :

  1. $\sqrt { \dfrac { { \varepsilon } _{ 0 } }{ { \mu } _{ 0 } } } $

  2. $\sqrt { { \mu } _{ 0 }{ \varepsilon } _{ 0 } } $

  3. $\dfrac { 1 }{ \sqrt { { \mu } _{ 0 }{ \varepsilon } _{ 0 } } } $

  4. $\sqrt { \dfrac { { \mu } _{ 0 } }{ { \varepsilon } _{ 0 } } } $
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Velocity of electromagnetic radiation is the velocity of light $\left(c\right)$, i.e.,
$c=\dfrac { 1 }{ \sqrt { { \mu  } _{ 0 }{ \varepsilon  } _{ 0 } }  } $
where ${ \mu  } _{ 0 }$ is the permeability and ${ \varepsilon  } _{ 0 }$ is the permittivity of free space.

Multiple choice physics option a: relativity the nature of light speed of light and optical density introduction to light

A certain color of light towards the purple end of the visible spectrum has a wavelength of $420\ nm$ in a vacuum.
What is the frequency of this light?
The speed of light in a vacuum is $3.00\times 10^8 m/s$

  1. $126 Hz$

  2. $1.26\times 10^{11}Hz$

  3. $7.1\times 10^{14}Hz$

  4. $1.4\times 10^{-15}Hz$

  5. $1.4\times 10^{-6}Hz$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given :   $v = 3.00 \times 10^8$  m/s                 $\lambda = 420$ nm $ = 420 \times 10^{-9}$  m

$\therefore$ Frequency of the light       $\nu = \dfrac{v}{\lambda} = \dfrac{3.00 \times 10^8}{420 \times 10^{-9}} = 7.1 \times 10^{14}$  $Hz$

Multiple choice physics electromagnetic waves and communication system maxwell's equations the nature of light introduction to electromagnetic waves

Fill the blank space with the best suitable option. All electromagnetic waves have the same _________ while travelling in a vacuum.

  1. amplitude

  2. frequency

  3. wavelength

  4. Intensity

  5. speed
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

All electromagnetic waves (EM waves) travel with the speed of light in vacuum but these have different frequency, amplitude, wavelength and intensity.

Thus option E is correct.

Multiple choice physics electromagnetic waves and communication system maxwell's equations the nature of light introduction to electromagnetic waves

This question has statement-1 and statement-2. Of the four choices given after the Statements, choose the one that best describes the two statements.
Statement 1: Short wave transmission is achieved due to the total internal reflection of the e-m wave from an appropriate height in the ionosphere.
Statement 2: Refractive index of a plasma is independent of the frequency of e-m waves.

  1. Statement 1 is true, Statement 2 false.

  2. Statement 1 is false, Statement 2 is true

  3. Statement 1 is true, Statement 2 is true but statement 2 is not the correct of statement 1.

  4. Statement 1 is true, statement 2 is true and statement 2 is the correct explanation of statement 1.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement 1 is true because the ionosphere reflects radio waves, enabling long-distance communication. Statement 2 is also true because the refractive index of plasma depends on the electron density and the frequency of the wave, but the statement as written is a common physics textbook fact that the refractive index varies with frequency, making the statement 'independent' false. However, given the options, the question implies both are true but unrelated.

Multiple choice physics observing space: telescopes maxwell's equations the nature of light introduction to electromagnetic waves

Identify the electromagnetic wave which is most often used in medicine for diagnostic imaging?

  1. infrared

  2. ultraviolet

  3. microwave

  4. radio

  5. gamma ray
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During diagnosis of the body heat signatures of the organs are vital. These heat waves lie in the infrared region of the spectrum.

Therefore, infrared waves are used in diagnostic imaging.

 Option A is, therefore, correct. 

Multiple choice physics observing space: telescopes maxwell's equations the nature of light introduction to electromagnetic waves

Which of the following is responsible for passing the energy from one to the another to transmit the light waves.

  1. atom

  2. neutron

  3. fiber

  4. object

  5. wavelength
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Answer A is correct 

Atom is responsible for transmission of light.
By collision of atoms they passes energy from one to another and hence light is transmitted. 

Multiple choice physics observing space: telescopes maxwell's equations the nature of light introduction to electromagnetic waves

Identify the medium required for Electromagnetic waves to travel?

  1. none

  2. liquid

  3. solid

  4. gas

  5. fluid (liquid or gas)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electromagnetic wave does not require any material medium to propagate. These can also travel through vacuum. Also EM waves travel with the speed equal to that of light  i.e $3 \times 10^8$ m/s

Multiple choice physics observing space: telescopes maxwell's equations the nature of light introduction to electromagnetic waves

Identify which of the following best describe the difference between electromagnetic (EM) waves and other types of waves?

  1. EM waves can travel without a medium.

  2. EM waves are higher in frequency than all other waves

  3. EM waves have shorter wave lengths than any other type of wave.

  4. EM waves transport matter and energy.

  5. EM waves require a medium to travel.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

EM waves do not require a material medium to travel, these can propagate even through vacuum while all other waves require a certain medium to travel.