A double slit experiment is performed with light of wavelength 500 nm. A thin film of thickness 2 μm and refractive index 1.5, is introduced in the path of the upper beam. The location of the central maximum will:

Shift downwards by nearly two fringes

Shift upwards by nearly two fringes

An object is placed at a distance greater than twice the focal point distance from a concave mirror. The image formed by the mirror is:

virtual, upright and magnification greater than one.

real, inverted and magnification greater than one.

real, inverted and magnification less than one.

virtual, upright and magnification greater than one.

virtual, upright and magnification less than one

A corona around the moon is seen when we view it on a fogy or misty night. This is due to:

Dispersion of light by air born water droplets

Diffraction patterns of air born water droplets

Dispersion of light by air born water droplets

Scattering of light by air born water droplets

Formation of diffused image of moon

A ray passing through the focus of a concave mirror after reflection _______________.

deviates in such a way that, when projected backwards passes, through the focus

becomes parallel to the principal axis

deviates in such a way that, when projected backwards passes, through the focus

If 1 and 2 represent mediums, 'n' is refractive index and 'R' is radius of curvature, then the lens maker’s formula is written as __________.

1 / f = (n21 - 1)(1 / R1 + 1 / R2)

1 / f = (n21 - 1)(1 / R1 - 1 / R2)

Rainbow is formed due to

dispersion and total internal reflection

Complete the statement with correct option.In dispersion without deviation, __________

only red coloured ray is parallel to the incident ray

the emergent rays of all the colours are parallel to the incident ray.

all the rays are parallel, but not parallel to the incident ray.

yellow coloured ray is parallel to the incident ray

only red coloured ray is parallel to the incident ray

If a white light is used in Young’s double slit experiment, then a very large number of coloured fringes can be seen:

With first order violet fringes being closer to the central white fringes

First order red fringes being closer to the central white fringes

In a double slit experiment instead of taking slits of equal widths, one slit is made twice as wide as the other, then in the interference pattern

The intensity of the maxima increases and the minima has zero intensity

The intensities of both the maxima and the minima increases

The intensity of the maxima increases and the minima has zero intensity

The intensity of maxima decreases and that of minima increases

The intensity of maxima decreases and the minima has zero intensity

Interference was observed in interference chamber when air is present. Now the chamber is evacuated and if the same light is used, then for the same arrangement:

No interference pattern will be obtained

Exactly same interference pattern will be obtained with better contract

The fringe width is slightly decreased

The fringe width is slightly increased

In Young’s double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then in the interference pattern:

The intensity of maxima increases and the minima has zero intensity

The intensities of both the maxima and the minima increase

The intensity of maxima increases and the minima has zero intensity

The intensity of maxima decreases and that of the minima increases

The intensity of maxima decreases and the minima has zero intensity

245 + Mcqs in Wave Optics Page 5 McqOptions

201.	Light of wavelength 600 nm is incident normally on a diffraction grating 3.00 cm wide. If second order line is observed at an angle of 30°, what is the total number of lines on the grating?
A.	14500
B.	15000
C.	12500
D.	13500
Answer» D. 13500

Discussion

202.	Given below are four statements-(p) The second principal focus of a lens is the position of the object, real or virtual whose image is at infinity.(q) The second principal focus of a lens is the position of the image, real or virtual whose object is at infinity.(r) The first principal focus of a lens is the position of the object, real or virtual whose image is at infinity.(s) The first principal focus of a lens is the position of the image, real or virtual whose object is at infinity. Examine the above statements and find which among then are correct.
A.	(q) & (r)
B.	(p) & (s)
C.	(q) & (s)
D.	(p) & (r)
Answer» B. (p) & (s)

Discussion

203.	A double slit experiment is performed with light of wavelength 500 nm. A thin film of thickness 2 μm and refractive index 1.5, is introduced in the path of the upper beam. The location of the central maximum will:
A.	Remain unshifted
B.	Shift downwards by nearly two fringes
C.	Shift upwards by nearly two fringes
D.	Shift downwards by 10 fringes
Answer» D. Shift downwards by 10 fringes

Discussion

204.	If the absolute refractive indices of glass and water are 3 / 2 and 4 / 3 respectively, what will be the ratio of velocity of light in glass and water?
A.	3 : 4
B.	4 : 3
C.	8 : 7
D.	8 : 9
Answer» E.

Discussion

205.	A disorder in which a person cannot see a distant object clearly is called what?A. HypermetropiaB. Night BlindnessC. MyopiaD. Strabismus
A.	A
B.	D
C.	B
D.	C
Answer» E.

Discussion

206.	Light of wavelength 5800 Å is incident normally on a slit of width 0.20 mm. A diffraction pattern is observed on screen 2 m away from the slit. From the central bright fringe, the distance of the first dark fringe on either side is
A.	2.4 mm
B.	5.8 mm
C.	6.4 mm
D.	1.2 mm
Answer» C. 6.4 mm

Discussion

207.	In an interference pattern with two identical coherent sources, the intensity on the screen at a point where path difference is λ. is I0. The intensity at a point where path difference is λ /4, will be
A.	Zero
B.	I0/4
C.	I0/2
D.	I0
Answer» D. I0

Discussion

208.	A plano convex lens (μ = 1.5) with radius of curvature 20 cm is silvered at the curved surface. The power of the system is :
A.	15 D
B.	10 D
C.	5 D
D.	2.5 D
Answer» E.

Discussion

209.	Experimental observation in a single slit experiment show that the intensity has a central maximum at θ = 0 and other secondary maxima at θ = ______________. (where 'θ' is the angle between the central line and the line joining the midpoint of the slit of width 'a' to any point 'P' on the screen, 'λ' is the wavelength of the light and where n = ±1, ±2, ±3, ....)
A.	(n + 1 / 2) λ / a
B.	nλ / a
C.	(n + 1 / 2) a / λ
D.	na / λ
Answer» B. nλ / a

Discussion

210.	If the focal length of a convex lens is 50 cm, which one of the following is its power?
A.	+2 dioptre
B.	+0.02 dioptre
C.	-0.5 dioptre
D.	+0.5 dioptre
Answer» B. +0.02 dioptre

Discussion

211.	An object is placed at a distance greater than twice the focal point distance from a concave mirror. The image formed by the mirror is:
A.	real, inverted and magnification greater than one.
B.	real, inverted and magnification less than one.
C.	virtual, upright and magnification greater than one.
D.	virtual, upright and magnification less than one
Answer» C. virtual, upright and magnification greater than one.

Discussion

212.	A corona around the moon is seen when we view it on a fogy or misty night. This is due to:
A.	Diffraction patterns of air born water droplets
B.	Dispersion of light by air born water droplets
C.	Scattering of light by air born water droplets
D.	Formation of diffused image of moon
Answer» B. Dispersion of light by air born water droplets

Discussion

213.	Match the position of the image obtained with the position of an object placed in front of a convex lens. Position of the Image Position of an object placed in front of a convex lens A. Beyond the centre of curvature1. On the same side of the lens B. Between the centre of curvature and focal point2.On the other side of the lens between the centre of curvature and focal point C. Between the pole and focal point3.On the other side of the lens beyond the centre of curvature
A.	A - 2, B - 1, C - 3
B.	A - 3, B - 2, C - 1
C.	A - 2, B - 3, C - 1
D.	A - 3, B - 1, C - 2
Answer» D. A - 3, B - 1, C - 2

Discussion

214.	A ray passing through the focus of a concave mirror after reflection _______________.
A.	retraces the path it came from
B.	passes through the focus
C.	becomes parallel to the principal axis
D.	deviates in such a way that, when projected backwards passes, through the focus
Answer» D. deviates in such a way that, when projected backwards passes, through the focus

Discussion

215.	Match list one with list two and select the correct answers using the code given below the lists:List one (Disease)List two (Remedy)AHypermetropia1concave lensBPresbyopia2bifocal lensCMyopia3SurgeryDCataract4Convex lens Code:
A.	A-4, B-2, C-1, D-3
B.	A-4, B-1, C-2, D-3
C.	A-3, B-1, C-2, D-4
D.	A-3, B-2, C-1, D-4
Answer» B. A-4, B-1, C-2, D-3

Discussion

216.	A fish is at a depth of 12 cm from the surface of a lake, And a bird is at a height of 15 cm above the surface of the lake.The fish and the bird are on the same vertical line. The refractive index of water in the lake is \(\frac{4}{3}\). Find the apparent distance of fish as observed by the bird.
A.	21 cm
B.	27 cm
C.	31 cm
D.	24 cm
Answer» E.

Discussion

217.	At which place in front of a concave mirror when the object is kept, its image is not seen?
A.	Between P and F
B.	At F
C.	Between F and C
D.	At C
Answer» C. Between F and C

Discussion

218.	If 1 and 2 represent mediums, 'n' is refractive index and 'R' is radius of curvature, then the lens maker’s formula is written as __________.
A.	f = (n21 - 1)(1 / R1 - 1 / R2)
B.	1 / f = (n21 - 1)(1 / R1 + 1 / R2)
C.	f = (n21 + 1)(1 / R1 - 1 / R2)
D.	1 / f = (n21 - 1)(1 / R1 - 1 / R2)
Answer» E.

Discussion

219.	Circular patches are often observed on the ground when sunlight through the space between the leaves of a tree. This arises due to the optical phenomenon of:
A.	scattering
B.	diffraction
C.	interference
D.	polarisation
Answer» C. interference

Discussion

220.	_______ was the first to establish that white light is a combination of several component colours.
A.	Henry Cavendish
B.	Issac Newton
C.	C.V. Raman
D.	John Dalton
Answer» C. C.V. Raman

Discussion

221.	Diameter of the objective lens of a telescope is 250 cm. For light of wavelength 600 nm coming from a distant object, the limit of resolution of the telescope is close to:
A.	1.5 × 10-7 rad
B.	2.0 × 10-7rad
C.	3.0 × 10-7 rad
D.	4.5 × 10-7 rad
Answer» D. 4.5 × 10-7 rad

Discussion

222.	Rainbow is formed due to
A.	only reflection
B.	dispersion and total internal reflection
C.	diffraction
D.	scattering
Answer» C. diffraction

Discussion

223.	In the given English alphabets H, I, B and C, which of them produces the same mirror image?
A.	B and C only
B.	C and H only
C.	B and H only
D.	I and H only
Answer» E.

Discussion

224.	A convex lens is put 10 cm from a light source and it makes a sharp image on a screen, kept 10 cm from the lens. Now a glass block (refractive index 1.5) of 1.5 cm thickness is placed in contact with the light source. To get the sharp image again, the screen is shifted by a distance d. Then d is:
A.	1.1 cm away from the lens
B.	0
C.	0.55 cm towards the lens
D.	0.55 cm away from the lens
Answer» E.

Discussion

225.	Let light of wavelength 600 nm is coming from a star. The limit of resolution of a telescope with objective lens of diameter 254 cm will be nearly
A.	5.8 × 10-7 radian
B.	2.9 × 10-7 radian
C.	1.4 × 10-7 radian
D.	0.72 × 10-7 radian
Answer» C. 1.4 × 10-7 radian

Discussion

226.	A point object is placed at a distance of 15 cm on the principle axis of a convex lens of focal length 12 cm. On the other side of the lens, a convex mirror is placed at a distance of 20 cm from the lens such that the image formed by the combination coincides with the object itself. The focal length of the convex mirror is:
A.	60 cm
B.	40 cm
C.	15 cm
D.	20 cm
Answer» E.

Discussion

227.	In a Young’s double slit experiment, the path difference at a certain point on the screen between two interfering waves is \(\frac{1}{8}^{th}\) of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to
A.	0.80
B.	0.74
C.	0.94
D.	0.85
Answer» E.

Discussion

228.	Light is incident normally on a diffraction grating having 5000 lines/cm. Second order line is observed at an angle of 30°. What is the wavelength of light?
A.	6000 Å
B.	5800 Å
C.	4000 Å
D.	5000 Å
Answer» E.

Discussion

229.	An optical illusion which occurs mainly in desert during hot summer is based on the principle of
A.	Reflection
B.	Interference
C.	Dispersion
D.	Total internal reflection
Answer» E.

Discussion

230.	Complete the statement with correct option.In dispersion without deviation, __________
A.	the emergent rays of all the colours are parallel to the incident ray.
B.	all the rays are parallel, but not parallel to the incident ray.
C.	yellow coloured ray is parallel to the incident ray
D.	only red coloured ray is parallel to the incident ray
Answer» D. only red coloured ray is parallel to the incident ray

Discussion

231.	Optic fibers are mainly used for which of the following?
A.	Musical instruments
B.	Food industry
C.	Weaving
D.	Communication
Answer» E.

Discussion

232.	An unpolarised beam is incident at an angle 60° an a glass surface and after reflection it is linearly polarised. The approximate refractive index of the glass is:
A.	1.4
B.	1.5
C.	1.7
D.	1.6
Answer» D. 1.6

Discussion

233.	At sun rise and sun set the sky near the sun looks red due to _____?
A.	Dispersion of Light
B.	Scattering of Light
C.	Reflection of Light
D.	Diffusion of Light
Answer» C. Reflection of Light

Discussion

234.	In a Young’s double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is dipped in water of refractive index 4/3 without disturbing the arrangement, the new fringe width will be:
A.	0.30 mm
B.	0.40 mm
C.	0.53 mm
D.	0.2 mm
Answer» B. 0.40 mm

Discussion

235.	In Young’s double slit experiment, the two slits act as coherent sources of equal amplitude A and wavelength l. In another experiment with the same set up the two slits are of equal amplitude A and wavelength l but are incoherent. The ratio of the intensity of light at the mid-point of the screen in the first case to case to that in the second case is:
A.	1 : 2
B.	2 : 1
C.	4 : 1
D.	1 : 1
Answer» C. 4 : 1

Discussion

236.	If a white light is used in Young’s double slit experiment, then a very large number of coloured fringes can be seen:
A.	With first order violet fringes being closer to the central white fringes
B.	First order red fringes being closer to the central white fringes
C.	With a central white fringe
D.	With a central black fringe
Answer» D. With a central black fringe

Discussion

237.	In Young’s experiment, the wavelength of red light is 7.8 × 10–5 cm and that of blue light 5.2 × 10–5 cm. The value of n for which (n + 1) the blue bright band coincides with nth red band is:
A.	4
B.	3
C.	2
D.	1
Answer» D. 1

Discussion

238.	In a double slit experiment instead of taking slits of equal widths, one slit is made twice as wide as the other, then in the interference pattern
A.	The intensities of both the maxima and the minima increases
B.	The intensity of the maxima increases and the minima has zero intensity
C.	The intensity of maxima decreases and that of minima increases
D.	The intensity of maxima decreases and the minima has zero intensity
Answer» B. The intensity of the maxima increases and the minima has zero intensity

Discussion

239.	Two waves of intensities I and 4I superpose, then the maximum and minimum intensities produced are:
A.	5I and 3I
B.	9I and I
C.	9I and 3I
D.	5I and I
Answer» C. 9I and 3I

Discussion

240.	In Young’s double slit experiment, 12 fringes are observed to be formed in a certain segment of the screen, when light of wavelength 600 nm is used. If the wavelength of light is changed to 400 nm, number of fringes observed in the same segment of the screen is given by:
A.	12
B.	18
C.	24
D.	30
Answer» C. 24

Discussion

241.	In Young’s double slit experiment, the separation between the slits is halved and the distance between the slits and the screen is doubled. The fringe width is
A.	Unchanged
B.	Halved
C.	Doubled
D.	Quadrupled
Answer» E.

Discussion

242.	Interference was observed in interference chamber when air is present. Now the chamber is evacuated and if the same light is used, then for the same arrangement:
A.	No interference pattern will be obtained
B.	Exactly same interference pattern will be obtained with better contract
C.	The fringe width is slightly decreased
D.	The fringe width is slightly increased
Answer» E.

Discussion

243.	Two slits are separated by a distance of 0.5 mm and illuminated with light of l = 6000 Å. If the screen is placed 2.5 m from the slits. The distance of the third bright image from the centre will be:
A.	1.5 mm
B.	3 mm
C.	6 mm
D.	9 mm
Answer» E.

Discussion

244.	In Young’s double slit experiment, the aperture screen distance is 2 m. The fringe width is 1 mm. Light of 600 nm is used. If a thin plate of glass (m = 1.5) of thickness 0.06 mm is placed over one of the slits, then there will be a lateral displacement of the fringes by:
A.	0 cm
B.	5 cm
C.	10 cm
D.	15 cm
Answer» C. 10 cm

Discussion

245.	In Young’s double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then in the interference pattern:
A.	The intensities of both the maxima and the minima increase
B.	The intensity of maxima increases and the minima has zero intensity
C.	The intensity of maxima decreases and that of the minima increases
D.	The intensity of maxima decreases and the minima has zero intensity
Answer» B. The intensity of maxima increases and the minima has zero intensity

Discussion

Explore topic-wise MCQs in UPSEE.

Light of wavelength 600 nm is incident normally on a diffraction grating 3.00 cm wide. If second order line is observed at an angle of 30°, what is the total number of lines on the grating?

A double slit experiment is performed with light of wavelength 500 nm. A thin film of thickness 2 μm and refractive index 1.5, is introduced in the path of the upper beam. The location of the central maximum will:

If the absolute refractive indices of glass and water are 3 / 2 and 4 / 3 respectively, what will be the ratio of velocity of light in glass and water?

A disorder in which a person cannot see a distant object clearly is called what?A. HypermetropiaB. Night BlindnessC. MyopiaD. Strabismus

Light of wavelength 5800 Å is incident normally on a slit of width 0.20 mm. A diffraction pattern is observed on screen 2 m away from the slit. From the central bright fringe, the distance of the first dark fringe on either side is

In an interference pattern with two identical coherent sources, the intensity on the screen at a point where path difference is λ. is I0. The intensity at a point where path difference is λ /4, will be

A plano convex lens (μ = 1.5) with radius of curvature 20 cm is silvered at the curved surface. The power of the system is :

If the focal length of a convex lens is 50 cm, which one of the following is its power?

An object is placed at a distance greater than twice the focal point distance from a concave mirror. The image formed by the mirror is:

A corona around the moon is seen when we view it on a fogy or misty night. This is due to:

A ray passing through the focus of a concave mirror after reflection _______________.

Match list one with list two and select the correct answers using the code given below the lists:List one (Disease)List two (Remedy)AHypermetropia1concave lensBPresbyopia2bifocal lensCMyopia3SurgeryDCataract4Convex lens Code:

A fish is at a depth of 12 cm from the surface of a lake, And a bird is at a height of 15 cm above the surface of the lake.The fish and the bird are on the same vertical line. The refractive index of water in the lake is \(\frac{4}{3}\). Find the apparent distance of fish as observed by the bird.

At which place in front of a concave mirror when the object is kept, its image is not seen?

If 1 and 2 represent mediums, 'n' is refractive index and 'R' is radius of curvature, then the lens maker’s formula is written as __________.

Circular patches are often observed on the ground when sunlight through the space between the leaves of a tree. This arises due to the optical phenomenon of:

_______ was the first to establish that white light is a combination of several component colours.

Diameter of the objective lens of a telescope is 250 cm. For light of wavelength 600 nm coming from a distant object, the limit of resolution of the telescope is close to:

Rainbow is formed due to

In the given English alphabets H, I, B and C, which of them produces the same mirror image?

A convex lens is put 10 cm from a light source and it makes a sharp image on a screen, kept 10 cm from the lens. Now a glass block (refractive index 1.5) of 1.5 cm thickness is placed in contact with the light source. To get the sharp image again, the screen is shifted by a distance d. Then d is:

Let light of wavelength 600 nm is coming from a star. The limit of resolution of a telescope with objective lens of diameter 254 cm will be nearly

In a Young’s double slit experiment, the path difference at a certain point on the screen between two interfering waves is \(\frac{1}{8}^{th}\) of wavelength. The ratio of the intensity at this point to that at the centre of a bright fringe is close to

Light is incident normally on a diffraction grating having 5000 lines/cm. Second order line is observed at an angle of 30°. What is the wavelength of light?

An optical illusion which occurs mainly in desert during hot summer is based on the principle of

Complete the statement with correct option.In dispersion without deviation, __________

Optic fibers are mainly used for which of the following?

An unpolarised beam is incident at an angle 60° an a glass surface and after reflection it is linearly polarised. The approximate refractive index of the glass is:

At sun rise and sun set the sky near the sun looks red due to _____?

In a Young’s double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is dipped in water of refractive index 4/3 without disturbing the arrangement, the new fringe width will be:

If a white light is used in Young’s double slit experiment, then a very large number of coloured fringes can be seen:

In Young’s experiment, the wavelength of red light is 7.8 × 10–5 cm and that of blue light 5.2 × 10–5 cm. The value of n for which (n + 1) the blue bright band coincides with nth red band is:

In a double slit experiment instead of taking slits of equal widths, one slit is made twice as wide as the other, then in the interference pattern

Two waves of intensities I and 4I superpose, then the maximum and minimum intensities produced are:

In Young’s double slit experiment, 12 fringes are observed to be formed in a certain segment of the screen, when light of wavelength 600 nm is used. If the wavelength of light is changed to 400 nm, number of fringes observed in the same segment of the screen is given by:

In Young’s double slit experiment, the separation between the slits is halved and the distance between the slits and the screen is doubled. The fringe width is

Interference was observed in interference chamber when air is present. Now the chamber is evacuated and if the same light is used, then for the same arrangement:

Two slits are separated by a distance of 0.5 mm and illuminated with light of l = 6000 Å. If the screen is placed 2.5 m from the slits. The distance of the third bright image from the centre will be:

In Young’s double slit experiment, the aperture screen distance is 2 m. The fringe width is 1 mm. Light of 600 nm is used. If a thin plate of glass (m = 1.5) of thickness 0.06 mm is placed over one of the slits, then there will be a lateral displacement of the fringes by:

In Young’s double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then in the interference pattern: