Physics M.C.Q (1 Marks)

2. First minimum of the other

Explanation:

The Rayleigh criterion is the generally accepted criterion for the minimum resolvable detail - the imaging process is said to be diffraction-limited when the first diffraction minimum of the image of one source point coincides with the maximum of another.

3. Remain same.

Explanation:

On the introduction of a transparent sheet in front of one of the slits, the fringe pattern will shift slightly but the width will remain the same.

1. The intensity decreases in proportion for the distance squared.

Explanation:

A point source produces a spherical wavefront that moves in all the directions from the point.

Whereas the intensity at the wavelength is dependent on the distance and it follows the inverse square law. So, the intensity decreases with an increase in the distance from the source.

2. Refraction

Explanation:

In optical instruments, the lenses are used to form images by Refraction.

3. Yellow and black

Explanation:

When the yellow light of sodium lamp interferes constructively we get yellow bright band, and when they interfere destructively we get black bark band.

2. Constructive interference

Explanation:

Conceptual, anti node represents joining of all points in constructive interface as the amplitude is high.

3. Gradually changing to blue

Explanation:

As the star coming closer to the earth, the frequency of the light increase and the wavelength decrease due to doppler effect. So the colour should gradually change to blue.

5. Polarization.

Explanation:

Light in the form of a plane wave in space is said to be linearly polarized. Light is a transverse electromagnetic wave, but natural light is generally unpolarized, all planes of propagation being equally probable.

The process of making the light wave vibrated in a single plane is known as polarization.

4. Geometrical reconstruction of a wavefront

Explanation:

Huygens considered that light was propagated in longitudinal waves.

Huygen's concept explained the direction of propagation of light waves by geometrical reconstruction of wavefront.

4. All the above

Explanation:

since photons have momentum and energy, they can produce all the three stated effects.

2. Newton

Explanation:

Newton was the first to use corpuscular theory to explain the nature of light. He was able to successfully reflection and refraction using this theory.

2. The central fringe achromatic and coloured fringes for small path difference.

Explanation:

If white light is used a white centre fringe is observed, but all the other fringes have coloured edges, the blue edge being nearer the centre. Eventually the fringes overlap and a uniform white light is produced.

1. Laser beam

Explanation:

Monochromatic light is light made up of one single pure frequency.white light, which is light that contains all frequencies, That means the sum of red, yellow, green, blue and violet. Some light sources send out monochromatic light such as lasers beam.

3. Resolving power

Explanation:

By definition, resolving power of an optical instrument is its ability to show two closely adjacent point (closely spaced) as distinct as possible.

4. Having a constant phase difference.

Explanation:

For light waves emitted by two sources of light to remain coherent, the initial phase difference between waves should remain constant in time. If the phase difference changes continuously or randomly with time, then the sources are incoherent.

4. Polarization

Explanation:

The polarization phenomenon, verifies the transverse nature of light. Since sound has longitudinal nature, so it does not show polarization effect.

3. I and III only

Explanation:

Polarizers are used in industry to reveal stress patterns in machinery and tools. Sunglasses are used to protect the eyes by polarizing the light to reduce glare using the tailor-made material of the glasses.

1. x = c.

Explanation:

​The wave is travelling along the X-axis. So, it'll have planar wavefront perpendicular to the X-axis.

1. In same phase

Explanation:

Wave front by definition is the locus of points having same phase.

3. These are longitudinal

Explanation:

Sound waves are longitudinal waves.

1. Phase is same for all points.

Explanation:

The locus of all particles in a medium, vibrating in the same phase is called wave front.

The direction of propagation of light (ray of light) is perpendicular to the wave front.

A wave front is an imaginary surface where all particles lying on this vibrate in the same phase.

4. None of the above

Explanation:

Doppler effect refers to the change in wave frequency during the relative motion between a wave source and it's observer by considering that the Velocity of the observer with respect to the source velocity is negligible.

1. Expansion of the universe

Explanation:

Red shift is the increase in wavelength of light observed due to Doppler Effect of light, observed when objects recede from each other.

The red shift as observed in distant galaxies suggests that the galaxies are moving away from us and from each other. This tells that the universe is expanding.

3. Planar

Explanation:

when you considered it a large distance and measuring justice Mall section of it then it can be considered to be plane wavefront source at Infinity example the one coming from sun to earth surface is considered to be plain VU friend from light diverging from a point source will be spherical.

So, the wave front due to a source situated at infinity is planar.

4. Polarisation by double refraction

Explanation:

In 1669, another Danish scientist, Erasmus Bartholinus discovered the polarization of light by double refraction in Iceland spar (calcite).

1. Interference patterns are evident for light behaving as rays.

Explanation:

Interference patterns are explained using wave nature of light. You can learn more from youtube video "Interference of light".

1. Plane.

Explanation:

Wave travelling from a distant source always has plane wavefront.

1. Red Shift

Explanation:

When the wavelength of the light gets lengthened by the Doppler shift, we refer to the change as red shift.

1. All points are in the same phase.

Explanation:

A wavefront is the locus of points characterized by propagation of position of the same phase:

a propagation of a line in 1D, a curve in 2D or a surface for a wave in 3D.

3. The intensity of light as seen through the Polaroid shall go through a minimum but not zero for two orientations of the polaroid.

Solution:

Hint: If a light beam incidents at Brewster's angle, then the transmitted beam is always unpolarised and reflected beam is always polarised.

In the given diagram, the light beam incident from air to the glass slab at Brewster's angle (ip). Therefore, the incident ray represented by dot (.), is unpolarised and the reflected light represented by arrow, is plane polarized.

Since, the emergent ray is unpolarised.

Hence, the intensity cannot be zero when passes through polaroid.

2. 2I

Explanation:

I = I_max​ = 4I_0​

Now, I0​ is increased to 2I0​

So, I_{max ​}= 4(2I₀​) = 8I₀​ = 2I

So, maximum intensity is 2I

2. Huygen's theory

Explanation:

Huygens suggested that light may be a wave phenomenon produced by mechanical vibrations of an all pervading hypothetical homogenous medium called eather just like those in solids and liguid .This medium was supposed to be mass less with extremely high elasticity and very low density.

1. violet

1. Use a thicker film than the film used for the "red" bubble.

Explanation:

As to obtain a nice coloured pattern, the thickness of the film has to be similar to the wavelength of light and the bubbles are darkest where they are thinnest.

4. Polarization

Explanation:

As we know the reflection, refraction, diffraction can be demonstrated with sound waves in an air column but to have polarized waves, they first need to be transverse waves but sound waves are longitudinal. Sound waves are longitudinal so they cannot be polarised.

3. Christian Huygens

Explanation:

Christian Huygens postulated wave theory.

1. Wave theory of light

Explanation:

Huygene's wave theory assumed that the light travels slower in glass than in air. That means for a given geometrical distance in glass, there will be more waves of light than in same distance in air. Consequently, it would seem that wavelength of light decreases as light propagates through air-glass interface.

4. Thomas Young

Explanation:

Thomas Young demonstrated the phenomenon of interference in water waves.

In 1801, he presented a famous paper to the Royal Society entitled "On the Theory of Light and Colours" which described various interference phenomena, and in 1803 he performed his famous double-slit experiment.

2. Speed of light in water is smaller than the speed in vacuum.
3. Light shows interference.

Explanation:

Snell's Law, which states that the speed of light reduces on moving from a rarer to a denser medium, can be concluded from Huygens' wave theory and interference of light waves is based on the wave properties of light.

3. Both A & B

Explanation:

In photometry, luminous intensity is a measure of the wavelength-weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. The SI unit of luminous intensity is the candela (cd), an SI base unit.