Download App

Physics M.C.Q (1 Marks)

Wave Optics · Gujarat Board (GSEB) STD 12 Science (GSEB - English Medium). 176 questions.

Questions · Page 2 of 4

M.C.Q (1 Marks)

MCQ 511 Mark
Thin films like soap bubbles and oil floating on water can create colorful patterns. Which of the following explanations most accurately describes why this happens?
  • A
    Thin films contain many different colored chemicals.
  • B
    Thin films provide reflection from the front and back surfaces, and this creates interference patterns.
  • C
    Thin films polarize light which interferes with the unpolarized light to create colors.
  • D
    Thin films absorb some colors and allow others to reflect.
Answer
  1. Thin films provide reflection from the front and back surfaces, and this creates interference patterns.

Explanation:

The reason of colourful patterns on soap bubbles and oil on water is interference.

Infact, the reflected waves from upper and lower surfaces, get interference and produce colourful patterns.

View full question & answer→
MCQ 521 Mark
Astronomers can tell whether a star is approaching or receding from the earth. Identify by which of the following method they can predict this?
  • A
    Absorption spectra of the star
  • B
    Doppler shift of the starlight
  • C
    Temperature of the star
  • D
    Thermal signature of the star
Answer
  1. Doppler shift of the starlight

Explanation:

To predict the movement of a star, we compare the spectra of elements found in star (H, He Na etc.), first spectra which are obtained from star and second spectra from laboratory. If spectral lines of the spectra obtained from star, are shifting towards red end (called red shift) then star is going away from earth and if shifting is towards blue (called blue shift), then star is approaching the earth. This is Doppler's shift.

View full question & answer→
MCQ 531 Mark
The equation of a light wave is written as $\text{y}=\text{A}\ \sin(\kappa\text{x}-\omega\text{t}).$ Here, y represents:
  • A
    Displacement of either particles.
  • B
    Pressure in the medium.
  • C
    Density of the medium.
  • D
    Electric field.
Answer
  1. Electric field.

Explanation:

Light consists of mutually perpendicular electric and magnetic fields. So, the equation of a light wave is represented by its field vector.

View full question & answer→
MCQ 541 Mark
Which of the following statement is false:
  • A
    Sound and light wave exhibit interference.
  • B
    Sound and light wave exhibit diffraction.
  • C
    Light wave exhibits polarization while sound wave does not.
  • D
    Sound wave exhibits polarization while light wave does not.
Answer
  1. Sound wave exhibits polarization while light wave does not.

Explanation:

Polarization is a property of waves that can oscillate with more than one orientation. Electromagnetic waves such as light exhibit polarization, as do some other types of wave, such as gravitational waves.

Sound waves in a gas or liquid do not exhibit polarization, since the oscillation is always in the direction the wave travels.

View full question & answer→
MCQ 551 Mark
A very thin film in reflected white light appears:
  • A
    coloured
  • B
    white
  • C
    black
  • D
    red
Answer
  1. black

Explanation:

For very thin films the distance travelled inside the film is insignificant and so the two reflected waves are almost exactly out of phase with each other (due to the phase change at one surface); they interfere destructively and the film appears 'black'.

View full question & answer→
MCQ 561 Mark
Which of the following phenomenon can explain quantum nature of light:
  • A
    Photoelectric effect
  • B
    Interference
  • C
    Diffrection
  • D
    Polarisation
Answer
  1. Photoelectric effect

Explanation:

Photoelectric effect explain the quantum nature of light while interference, diffraction and polarization explain the wave nature of light.

View full question & answer→
MCQ 571 Mark
The angular spread of central maximum, in the diffraction pattern, does not depend on ______.
  • A
    The distance between the slit and sources
  • B
    Width of slit
  • C
    Wavelength of light
  • D
    Frequency of light
Answer
  1. The distance between the slit and sources

Explanation:

Angular spread of central maxima $=(\theta)=\frac{\lambda}{\text{b}}​$

Where $\lambda$ = wavelength of light

b = width of slit

⇒ Clearly, it does depends on the distance between slit and sources.

View full question & answer→
MCQ 581 Mark
The radius of a wavefront as the waves propagate:
  • A
    Decreases
  • B
    Increases
  • C
    Becomes zero
  • D
    Sometimes decreases and sometimes increases.
Answer
  1. Increases

Explanation:

As the waves propagates, it goes on creating secondary sources of light, resulting in increase in its radius.

View full question & answer→
MCQ 591 Mark
Wave front formed by the collimator of a spectrometer:
  • A
    Plane
  • B
    Spherical
  • C
    Cylindrical
  • D
    Paraboloidal
Answer
  1. Spherical

Explanation:

Wave front formed by the collimator of a spectrometer is a plane wave front, when r lit is in the focus.

View full question & answer→
MCQ 601 Mark
Antinodal curves correspond to _____ interference.
  • A
    Constructive
  • B
    Destructive
  • C
    Where intensity is less than maximum but not completely zero.
  • D
    None of these
Answer
  1. Constructive

Explanation:

Antinodal curves correspond to constructive interference.

View full question & answer→
MCQ 611 Mark
If light is passed through a double-slit opening and falls onto a screen, Identify the pattern produced on the screen.
  • A
    A bright central band of light with slightly diminished, alternating bright and dark bands.
  • B
    A bright central band of light with tiny lines toward the edges of the screen.
  • C
    A large circle of light with tiny circles around it
  • D
    one antinode and no nodes.
Answer
  1. A bright central band of light with slightly diminished, alternating bright and dark bands.

Explanation:

When light is passed through a double slit opening, light from the two slits interfere at different points in the screen, forming alternating bright and dark fringes due to constructive and destructive interference respectively. However the intensities of higher order bands is slightly diminished.

Such an arrangement was first studied by Young, and has been since called Young's Double Slit Setup.

View full question & answer→
MCQ 621 Mark
During the 19th century, light was considered to be a stream of particles called:
  • A
    Atoms
  • B
    Electrons
  • C
    Corpuscles
  • D
    Quantas
Answer
  1. Corpuscles

Explanation:

The corpuscular theory of light is proposed by newton in 1704. It is referred as particle theory or newton’s theory of light.

According to this theory,

Light is made up of tiny particles called corpuscles having negligible mass. These particles (corpuscles) are perfectly elastic.

These tiny particles always travel in straight line in all directions.

These corpuscles ravel at very high velocity.

These corpuscles are of different sizes. The different color of light is due to different sizes.

View full question & answer→
MCQ 631 Mark
Suppose the medium in the previous question is water. Select the correct option(s) from the list given in that question.
  • A
    vA > vB > vC
  • B
    vA < vB < vC
  • C
    vA = vB = vC
  • D
    $\text{v}_\text{B}=\frac{1}{2}(\text{v}_\text{A}+\text{v}_\text{C})$
Answer

  1.  $\text{v}_\text{A}>\text{v}_\text{B}>\text{v}_\text{C}$

  2. $\text{v}_\text{B}=\frac{1}{2}(\text{v}_\text{A}+\text{v}_\text{C})$

Explanation:

Since the speed of light is a universal constant,

$\text{v}_\text{A}=\text{v}_\text{B}=\text{v}_\text{C}=3\times 10^8\text{m/s}$

$\text{v}_\text{B}=\frac{1}{2}(\text{u}_\text{A}+\text{u}_\text{C})$ This expression also implies that vA = vB = vC 

View full question & answer→
MCQ 641 Mark
The transverse nature of light is shown by:
  • A
    Interference of light
  • B
    Refraction of light
  • C
    Polarization of light
  • D
    Dispersion of light
Answer
  1. Polarization of light

Explanation:

Polarisation of light establishes that light are transverse in nature, otherwise it was believed that they are longitudinal waves, like the sound waves.

View full question & answer→
MCQ 651 Mark
Light is:
  • A
    Wave phenomenon.
  • B
    Particle phenomenon
  • C
    Both particle and wave phenomenon.
Answer
  1. Both particle and wave phenomenon.

Explanation:

Light shows photoelectric effect and Compton effect, which depicts its particle nature. It also shows interference and diffraction, which depicts the wave nature of light.

View full question & answer→
MCQ 661 Mark
The angular resolution of a telescope of 10cm diameter at a wavelength of 5000$\mathring{\text{A}}$ is of the order of:
  • A
    106 rad
  • B
    10−2 rad
  • C
    10−4 rad
  • D
    10−5 rad
Answer
  1. 10−5 rad

Explanation:

$\text{R}=\frac{1}{\Delta\theta}$

$=\frac{\text{a}}{1.22\lambda}$

$\frac{1}{\Delta\theta}=\frac{0.10}{1.22\times5000\times10^{-10}}$

$\Delta\theta=6.1\times10^{-6}\text{rad}$

View full question & answer→
MCQ 671 Mark
If Young's double slit experiment is performed in water:
  • A
    The fringe width will decrease.
  • B
    The fringe width will increase.
  • C
    The fringe width will remain unchanged.
  • D
    There will be no fringe.
Answer
  1. The fringe width will decrease.

Explanation:

As fringe width is proportional to the wavelength and wavelength of light is inversely proportional to the refractive index of the medium,

Here,

$\lambda_\text{M}=\frac{\lambda}{\eta}$

$\lambda_\text{M}$ = wavelength in medium

$\lambda$ = wavelength in vacuum

$\eta$ = refractive index of medium

Hence, fringe width decreases when Young's double slit experiment is performed under water.

View full question & answer→
MCQ 681 Mark
If the source of light used in a Young's double slit experiment is changed from red to violet:
  • A
    The fringes will become brighter.
  • B
    Consecutive fringes will come closer.
  • C
    The intensity of minima will increase.
  • D
    The central bright fringe will become a dark fringe.
Answer
  1. Consecutive fringes will come closer.

Explanation:

Fringe width, $\beta=\frac{\lambda\text{D}}{\text{d}}$

Wavelength of red light is greater than wavelength of violet light; so, the fringe width will reduce.

View full question & answer→
MCQ 691 Mark
Consider sunlight incident on a slit of width 104A. The image seen through the slit shall.
  • A
    Be a fine sharp slit white in colour at the center.
  • B
    A bright slit white at the center diffusing to zero intensities at the edges.
  • C
    A bright slit white at the center diffusing to regions of different colours.
  • D
    Only be a diffused slit white in colour.
Answer
  1. Be a fine sharp slit white in colour at the center.

Solution:

Key concept:

Diffraction of Light is the phenomenon of bending of light around the comers of an obstacle/aperture of the size of the wavelength of light.

Size of the slit is very large compared to wavelength

Size of the slit is comparable to wavelenght

In figure (A), no diffraction phenomenon is observed as the size of slit is weary large compared to wavelength. But in figure(B), there will be diffraction of light as size of slit is compared to the wavelength of light incident.

Here in the question it is given, width of the slit

$\text{b}=10^4\mathring{\text{A}}=10^4\times10^{-10}\text{m}$

$=10^{-6}\text{m}=1\text{pm}$

Wavelength of (visible) sunlight varies from $4000\mathring{\text{A}}\text{ to }8000\mathring{\text{A}}$.

Hence the width of slit is comparable to that of wavelength, hence diffraction occurs with maxima at centre. So, at the centre all colours appear, i.e., mixing of colours form white patch at the centre.

View full question & answer→
MCQ 701 Mark
Which of the following properties show that light is a transverse wave?
  • A
    Reflection.
  • B
    Interference.
  • C
    Diffraction.
  • D
    Polarization.
Answer
  1. Polarization.

Explanation:

Reflection, interference and diffraction are the phenomena shown by both transverse waves and longitudinal waves. Polarization is the phenomenon shown only by transverse waves.

View full question & answer→
MCQ 711 Mark
The wave theory of light, in its original form, was first postulated by.
  • A
    Isaac Newton
  • B
    Christian Huygens
  • C
    Thomas Young
  • D
    Augustin Jean Fresnel
Answer
  1. Christian Huygens

Explanation:

In 1678, Dutch physicist, Christian Huygens, believed that the light was made up of waves vibrating up and down perpendicular to the direction of the light travels and therefore formulated away of visualising wave propagation.

This becomes know as Huygens principle. Huygens theory was the successful theory of light in three dimensions. Huygens suggested that the light wave peaks form from surfaces like the layers of onion. In a vacuum or other uniform mediums the light waves are spherical and these wave surfaces advance or spread out as they travel at the speed if light.

This theory explains why light shining through a pinhole or slitwall spread out rather than going in straight lines.

View full question & answer→
MCQ 721 Mark
When light is refracted, which of the following does not change?
  • A
    Wavelepgth.
  • B
    Frequency.
  • C
    Velocity.
  • D
    Amplitude.
Answer
  1. Frequency.

Explanation:

Frequency of a light wave doesnt change on changing the medium of propagation of light.

View full question & answer→
MCQ 731 Mark
When a drop of oil is spread on a water surface, it displays beautiful colours in daylight because of:
  • A
    Disperson of light.
  • B
    Reflection of light.
  • C
    Polarization of light.
  • D
    Interference of light.
Answer
  1. Interference of light.

Explanation:

Interference effect is produced by a thin film (coating of a thin layer of a translucent material on a medium of different refractive index which allows light to pass through it). ln the present case, oil floating on water forms a thin film on the surface of water, leading to the display of beautiful colours in daylight because of the interference of sunlight.

View full question & answer→
MCQ 741 Mark
According to Newton, different colors of light are due to the difference in _______ of the corpuscles.
  • A
    mass
  • B
    nature
  • C
    shape
  • D
    size
Answer
  1. size

Explanation:

Corpuscles are single, infinitesimally small, particles which have shape, size, color, and other physical properties.

View full question & answer→
MCQ 751 Mark
Which of the following sources gives best monochromatic light?
  • A
    A candle.
  • B
    A bulb.
  • C
    A mercury tube.
  • D
    A laser.
Answer
  1. A laser.

Explanation:

Among the given sources, laser is the best coherent source providing monochromatic light with constant phase difference.

View full question & answer→
MCQ 761 Mark
Light waves travel in vaccum along the y-axis. Then the wave front is:
  • A
    y = constant
  • B
    x = constant
  • C
    z = constant
  • D
    x+y+z = constant
Answer
  1. y = constant

Explanation:

waves front are plane perpendicular to the direction of rays.

so, as light is traveling along y - axis, plane perpendicular to y - axis is the x-z plane with any constant value of y.

so, y = constant is the wave front plane

View full question & answer→
MCQ 771 Mark
In an astronomical microscope, the focal length of the objective is made:
  • A
    Shorter than that of the eye piece
  • B
    Greater than that of the eye piece
  • C
    Half of the eye piece
  • D
    Equal to that of the eye piece
Answer
  1. Greater than that of the eye piece

Explanation:

In an Astronomical telescope, the objective lens has a greater radius than the eyepiece.

Thus the objective lens has a greater focal length than the eyepiece.

View full question & answer→
MCQ 781 Mark
The wavefronts of a light wave travelling in vacuum are given by x + y + z = c. The angle made by the direction of propagation of light with the X-axis is:
  • A
    $0^\circ$
  • B
    $45^\circ$
  • C
    $90^\circ$
  • D
    $\cos^{-1}\Big(\frac{1}{\sqrt{3}}\Big)$
Answer
  1. $\cos^{-1}\Big(\frac{1}{\sqrt{3}}\Big)$

Explanation:

On writing the given equation in the plane equation form lx + my + nz = p,

Where l2 + m2 + n2 and p > 0, we get:

$\frac{1}{\sqrt{3}}\text{x}+\frac{1}{\sqrt{3}}\text{y}+\frac{1}{\sqrt{3}}\text{z}=\frac{\text{c}}{\sqrt{3}}$

If $\theta$ is the angle between the normal and +x axis, then

$\cos\theta=\frac{1}{\sqrt{3}}$

$\Rightarrow\theta=\cos^{-1}\Big(\frac{1}{\sqrt{3}}\Big) $

View full question & answer→
MCQ 791 Mark
The phenomenon of rotation of plane polarized light is called:
  • A
    Kerr effect
  • B
    Double refraction
  • C
    Optical activity
  • D
    Dichroism
Answer
  1. Optical activity

Explanation:

The phenomenon of rotation of plane polarized light is called optical activity.

View full question & answer→
MCQ 801 Mark
In which of the following the final image is erect? 
  • A
    Compound microscope
  • B
    Astronomical telescope
  • C
    Simple microscope
  • D
    All of the above
Answer
  1. Simple microscope

Explanation:

The image formed by the Compound microscope and Astronomical telescope is inverted,but in case of Simple microscope it form erect image.

View full question & answer→
MCQ 811 Mark
An observer on earth observes that wave length of spectral line in spectrum of a milky way shifts towards red end of spectrum. According to the observer, the milky-way is:
  • A
    Approaching the earth
  • B
    Receding away from the earth
  • C
    Stationary
  • D
    Rotating about its own axis
Answer
  1. Receding away from the earth

Explanation:

When an object moves away from us, its light waves are stretched into lower frequencies or longer wavelengths, and we say that the light is redshifted.

It also explain the expanding nature of universe. Shifting towards red end means wavelength is increasing. There, milkyway is receding away from earth.

View full question & answer→
MCQ 821 Mark
A thin slice is cut out of a glass cylinder along a plane parallel to its axis. The slice is placed on a flat glass plae as shown in figure. The observed interference fringes from this combination shall be:

  • A
    Straight
  • B
    Circular
  • C
    Equally spaced
  • D
    Having fringe spacing which increases as we go outward.
Answer
  1. Straight

Explanation:

The locus of the equal path difference consists in lines going parallel to the axis of cylinder. 

Therefore, interference fringes will be straight.

View full question & answer→
MCQ 831 Mark
What type of diffraction takes place in case of Young's double slit experiment?
  • A
    Fresnal type
  • B
    Fraunhofer type
  • C
    neigher Fresnel type nor Fraunhofer type
  • D
    sometimes Fresnel type sometimes Frunhofer types
Answer
  1. Fraunhofer type
View full question & answer→
MCQ 841 Mark
Using visible light what is the shortest wavelength which can be measured?

  • A
    200nm
  • B
    100nm
  • C
    350nm
  • D
    175nm
Answer
  1. 100nm
View full question & answer→
MCQ 851 Mark
The inability of a lens to bring all the rays coming from a point object to focus at one single point is called:
  • A
    Spherical aberration
  • B
    Parallex
  • C
    Optical illusion
  • D
    none
Answer
  1. Spherical aberration
View full question & answer→
MCQ 861 Mark
Two identical lights sources S1​ and S2​ emit the light of same wavelength $\lambda$. These light rays will exhibit interference if:
  • A
    Their phase difference remain constant.
  • B
    Their phase difference is distributed randomly.
  • C
    Their light intensities remain constant.
  • D
    Their light intensities change continuously.
Answer
  1. Their phase difference remain constant.

Explanation:

For interference to take place the light sources need to be either in phase or have a constant phase difference. In case the phase difference keeps changing the interference pattern will keep on changing, as a result of interference pattern will be observed.

View full question & answer→
MCQ 871 Mark
When a drop of oil is spread on a water surface, it displays beautiful colors in daylight because of:
  • A
    Dispersion of light
  • B
    Reflection of light
  • C
    Polarization of light
  • D
    Interference of light
Answer
  1. Interference of light

Explanation:

When a drop of oil is spread on a water surface, it displays beautiful colors in daylight because the oil film is only a few nano-meters thick. Some of the light is reflected off the top surface and some the bottom surface. Because the thickness of the oil film is about the same as the wavelength of the light the two reflected rays interfere with each other.

View full question & answer→
MCQ 881 Mark
If the apertature of a telescope is decreased the resolving power will:
  • A
    Increases
  • B
    Decreases
  • C
    Remain same
  • D
    Zero
Answer
  1. Decreases

Explanation:

Resolving power of a telescope $=\frac{\text{a}}{1.22\lambda}$

where a is the aperture of the telescope.

Thus resolving power∝ aperture.

Hence, if the aperture of telescope decreases, the resolving power decreases.

View full question & answer→
MCQ 891 Mark
In a Young's double slit experiment, the source is white light. One of the holes is covered by a red filter and another by a blue filter. In this case:
  • A
    There shall be alternate interference patterns of red and blue.
  • B
    There shall be an interference pattern for red distinct from that for blue.
  • C
    There shall be no interference fringes.
  • D
    There shall be an interference pattern for red mixing with one for blue.
Answer
  1. There shall be no interference fringes.

Solution:

We know that, for the interference pattern to be formed on the screen, the sources should be coherent and emits lights of same frequency and wavelength.

In a Young's double-slit experiment, if one of the holes is covered by a red filter and another by a blue filter, then only red and blue lights are present due to alteration. In Young's double-slit experiment, a monochromatic light is used for the formation of fringes on the screen.

Therefore, there shall be no interference fringes.

View full question & answer→
MCQ 901 Mark
A light wave can travel:
  • A
    In vacuum.
  • B
    In vacuum only.
  • C
    In a material medium.
  • D
    In a material medium only
Answer
  1. In vacuum.
  1. In a material medium.

Explanation:

Light is an electromagnetic wave that can travel through vacuum or any optical medium.

View full question & answer→
MCQ 911 Mark
Two source S1 and S2 of intensity I1 and I2 are placed in front of a screen [Fig. (a)]. The patteren of intensity distribution seen in the central portion is given by Fig. (b).

In this case which of the following statements are true.
  • A
    S1 and S2 have the same intensities.
  • B
    S1 and S2 have a constant phase difference.
  • C
    S1 and S2 have the same phase.
  • D
    S1 and S2 have the same wavelength.
Answer
  1. S1 and S2 have the same intensities.
  2. S1 and S2 have a constant phase difference.
  1. S1 and S2 have the same wavelength.

Solution:

Key concept:

  1. For getting the sustained interference the initial phase difference between the interfering waves must remain constant, i.e., sources should be coherent.

For two coherent sources, the resultant intensity is given bt $\text{I}=\text{I}_1+\text{I}_2+2\sqrt{\text{I}_1\text{I}_2}\cos\phi$.

  1. Resultant intensity at the point of observation will be maximum.

$\text{I}_{\text{max}}=\text{I}_1+\text{I}_2+2\sqrt{\text{I}_1\text{I}_2}$

$\text{I}_\text{max}=(\sqrt{\text{I}_1}+\sqrt{\text{I}_2})^2$

  1. Resultant intensity at the point of observation will be minimum.

$\text{I}_{\text{max}}=\text{I}_1+\text{I}_2+2\sqrt{\text{I}_1\text{I}_2}$

$\text{I}_\text{max}=(\sqrt{\text{I}_1}+\sqrt{\text{I}_2})^2$

View full question & answer→
MCQ 921 Mark
Wave front means:
  • A
    All particles in it have same phase.
  • B
    Few particles are in same phase, rest are in opposite phase.
  • C
    All particles have opposite phase of vibrations.
  • D
    All particles have random vibrations.
Answer
  1. All particles in it have same phase.

Explanation:

It is the imaginary surface representing corresponding points pf a wave that vibrate in unison. When identical waves having a common origin travel through a homogeneous medium, the corresponding crests and troughs at any instant phase.

View full question & answer→
MCQ 931 Mark
Huygen's wave theory allows us to know:
  • A
    The wavelength of the wave.
  • B
    The velocity of the wave.
  • C
    The amplitude of the wave.
  • D
    The propagation of the wave front.
Answer
  1. The propagation of the wave front.

Explanation:

Huygen's wave theory explain the propagation of the wave front.

View full question & answer→
MCQ 941 Mark
In Young's interference experiment, if the slits are of unequal width, then:
  • A
    No fringes will be formed
  • B
    The positions of minimum intensity will not be completely dark.
  • C
    Bright fringe as displaced from the original central position.
  • D
    Distance between two consecutive dark fringes will not be equal to the distance between two consecutive right fringes.
Answer
  1. The positions of minimum intensity will not be completely dark.

Explanation:

Unequal width of slits will cause unequal intensity of lights entering from both slits.

As a result, during interference complete cancelling of light intensity will not take place at regions of otherwise dark fringe.

As the value of $\beta$ does not depend on intensity of light, there will be no shifting of fringes as well as no change in fringe width.

View full question & answer→
MCQ 951 Mark
Light waves can be polarised because they:
  • A
    Have high frequencies
  • B
    Have short wavelength
  • C
    Are transverse
  • D
    Can be reflected
Answer
  1. Are transverse

    Explanation:

    Polarisation of light waves is possible only because they can oscillate in more than one orientation i.e., they are transverse in nature. It has no dependence on its wavelength and frequencies.

View full question & answer→
MCQ 961 Mark
When light is refracted into a medium:
  • A
    Its wavelength and frequency both increase
  • B
    Its wavelength increases but frequency remains unchanged
  • C
    Its wavelength decreases but frequency remains unchanged.
  • D
    Its wavelength and frequency both decrease.
Answer
  1. Its wavelength decreases but frequency remains unchanged.

Explanation:

Frequency of a light wave, as it travels from one medium to another, always remains unchanged, while wavelength decreases.

Decrease in the wavelength of light entering a medium of refractive index $\mu$, is given by,

$\lambda_\text{M}=\frac{\lambda}{\mu},$

Where $\lambda_\text{M}$ = wavelength in medium

$\lambda$ = wavelength in vacuum

$\mu$ = refractive index

View full question & answer→
MCQ 971 Mark
A person shines a coherent light of a bulb through an object, A, which produces a pattern of concentric rings on a screen, B. A is most likely:

  • A
    A polarization filter
  • B
    A single-slit
  • C
    A prism
  • D
    A sheet with a pinhole
Answer
  1. A sheet with a pinhole

Explanation:

A polarization filter will limit the light vectors in a single plane i.e. polarization.

A prism will split the light i.e. dispersion .

A slit system will make a diffraction pattern on screen B, but in this pattern, fringes are straight.

Due to its circular size, a pinhole will produce diffraction pattern on screen B in the forms of concentric rings.

View full question & answer→
MCQ 981 Mark
Light waves exhibit polarization but sound waves do not exhibit polarization because they are not:
  • A
    Longitudinal
  • B
    Coherent
  • C
    Dispersive
  • D
    Transverse
Answer
  1. Transverse

Explanation:

Only transverse waves can exhibit polarization.

Light waves are transverse waves whereas sound waves are longitudinal waves, hence sound waves can not be polarized.

View full question & answer→
MCQ 991 Mark
The shape of wave front at a very large distance from source is ______.
  • A
    Circular
  • B
    Spherical
  • C
    Cylindrical
  • D
    Plane
Answer
  1. Plane

Explanation:

Due to the large distance, the radius of the wavefront can be considered as large (infinity) and hence, a wavefront is almost plane.

View full question & answer→
MCQ 1001 Mark
A white light is passed through the two narrow slits and produced a pattern of alternating bright and dark lines on the screen as shown above. What will effects on the central bright band , if the distance between screen and slits are increased?

  • A
    Become wider
  • B
    Become narrower
  • C
    Remain unchanged
  • D
    Disappear completely
Answer
  1. Become wider

Explanation:

The setup shown is that of Young's Double Slit Experiment.

The fringe width in the experiment is given as $\beta=\frac{\text{D}\lambda}{\text{d}}​$

where d is the distance between the slits, D is the distance between screen and slits.

Hence the central fringe also widens when distance between screen and slits increases.

View full question & answer→
Generate Paper FreeAll Wave Optics topics