Wave Optics Test

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Wave Optics Test - 62

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Weekly Quiz Competition

Question 1
1 / -0

Which of the following can not be polarised

A
Radio waves

B
Ultraviolet rays

C
Infrared rays

D
Ultrasonic waves

Solution

Ultrasonic waves are longitudinal waves.
Question 2
1 / -0

By Huygens wave theory of light, we cannot explain the phenomenon of

A
Interference

B
Diffracton

C
Photoelectric effect

D
Polarisation

Solution

Huygen's wave theory fails to explain the particle nature of light (i.e. photoelectric effect)
Question 3
1 / -0

In Young's double slit experiment the spacing between two slits is $$0.1\ mm$$. If the screen is kept at a distance of $$1.0\ m$$ from the from the slits and the wavelength of light is $$5000\ \overset {o}{A}$$, then the fringe width is

A
$$1.0\ cm$$

B
$$1.5\ cm$$

C
$$0.5\ cm$$

D
$$2.0\ cm$$

Solution

$$\beta =\dfrac {\lambda D}{d}$$

$$=\dfrac {5000\times 10^{-10}\times 1}{0.1\times 10^{-3}}m$$

$$=5\times 10^{-3}m=0.5\ cm$$
Question 4
1 / -0

The resolving limit of healthy eye is about

A
$$1'$$ or $$\left( \dfrac{1}{60}\right)^o$$

B
$$1"$$

C
$$1^o$$

D
$$\dfrac{1}{60}"$$

Solution

Resolving limit of eye is one minute $$(1')$$.
Question 5
1 / -0

Wave which cannot travel in vacuum is

A
$$X-$$ rays

B
Infrasonic

C
Ultraviolet

D
Radiowaves

Solution

Infrasionic waves because they are mechanical waves.
Question 6
1 / -0

Which of the following statement is wrong

A
Infrared photon has more energy than the photon of visible light

B
Photographic plates are sensitive to ultraviolet rays

C
Photographic plates can be made sensitive to infrared rays

D
Infrared rays are invisible but can cast shadows like visible light rays

Solution

Photographic plates uses photoelectric effect to produce the spectrum. So, if a electromagnetic ray is projected on it, it will be sensitive towards it.
Hence, its sensitive to both ultraviolet and infrared rays.
The infrared rays do cast shadows like visible rays as they are not able to pass through most opaque objects just like visible rays.
Now, we know that the energy of a electromagnetic wave is given by,
$$E=\dfrac{hc}{\lambda}$$
or, we can say that $$E\propto \dfrac{1}{\lambda}$$
Hence, if the wavelength decreases the energy will increase. Or, the lesser the wavelength the higher the energy. Infrared photons will have higher wavelength than that of visible light. Hence, its energy should be lesser than than visible light.
So, the wrong option is (A).
Question 7
1 / -0

which one of the following phenomenon is not explained by Huygen's construction of wavefront

A
Refraction

B
Reflection

C
Differection

D
Origin of spectra

Solution

Origin of spectra is not explained by Huygen's theory.
Question 8
1 / -0

In Young's double slit experiment if $$L$$ is the distance between the slits and the screen upon which interference pattern is observed $$x$$ is the average distance between the adjacent fringes and $$d$$ being the slit separation. The wavelength of light is given by

A
$$\dfrac {xd}{L}$$

B
$$\dfrac {xL}{d}$$

C
$$\dfrac {Ld}{x}$$

D
$$\dfrac {1}{Ldx}$$

Solution

We know that fringe width $$\beta =\dfrac {D \lambda}{d}$$
$$\therefore x=\dfrac {L \lambda}{d}\Rightarrow \lambda =\dfrac {xd}{L}$$
Question 9
1 / -0

Ray diverging from a point source form a wave front that is

A
Cylindrical

B
Spherical

C
Plane

D
Cubical

Solution
Question 10
1 / -0

Young's experiment is performed in air and then performed in water, the fringe width

A
Will remain same

B
Will decrease

C
Will increase

D
Will be infinite

Solution

The fringe width is given as:
$$\beta=\dfrac{D\lambda}{d}$$
$$\beta \propto \lambda$$

We know that the wavelength is inversely proportional to the refractive index of the medium.
$$ \ \therefore \lambda\propto \dfrac {1}{\mu}$$

So, the fringe width will decrease as the refractive index of water is higher than that of air.

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Re-Attempt Weekly Quiz Competition

Wave Optics Test - 62

Result

Wave Optics Test - 62

Score

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Rank

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SHARING IS CARING

Question 1

Radio waves

Ultraviolet rays

Infrared rays

Ultrasonic waves

Solution

Question 2

Interference

Diffracton

Photoelectric effect

Polarisation

Solution

Question 3

$$1.0\ cm$$

$$1.5\ cm$$

$$0.5\ cm$$

$$2.0\ cm$$

Solution

Question 4

$$1'$$ or $$\left( \dfrac{1}{60}\right)^o$$

$$1"$$

$$1^o$$

$$\dfrac{1}{60}"$$

Solution

Question 5

$$X-$$ rays

Infrasonic

Ultraviolet

Radiowaves

Solution

Question 6

Infrared photon has more energy than the photon of visible light

Photographic plates are sensitive to ultraviolet rays

Photographic plates can be made sensitive to infrared rays

Infrared rays are invisible but can cast shadows like visible light rays

Solution

Question 7

Refraction

Reflection

Differection

Origin of spectra

Solution

Question 8

$$\dfrac {xd}{L}$$

$$\dfrac {xL}{d}$$

$$\dfrac {Ld}{x}$$

$$\dfrac {1}{Ldx}$$

Solution

Question 9

Cylindrical

Spherical

Plane

Cubical

Solution

Question 10

Will remain same

Will decrease

Will increase

Will be infinite

Solution

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