Q.1
A beam of monochromatic light is refracted from vacuum into a medium of refractive index 1.5, the wavelength of refracted light will be... [ CBSE-PMT 1991]
  • a) dependent on intensity of refracted light
  • b) same
  • c) smaller
  • d) larger
Q.2
A point source of light is placed 4m below the surface of water of refractive index 5/The minimum diameter of disc, which should be over the source, on the surface of water to cut off all light coming out of water is .. [ CBSE-PMT 1994]
  • a)∞
  • b) 6m
  • c)4m
  • d)3m
Q.3
An achromatic combination of lenses is formed by joining.. [ CBSE-PMT 1995]
  • a) 2 convex lenses
  • b) 2 concave lenses
  • c)1 convex and 1 concave lens
  • d)1 convex and 1 plane mirror
Q.4
A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will [ CBSE-PMT 2003]
  • a) remain unchanged
  • b) become zero
  • c)become infinite
  • d)becomes small, but non-zero
Q.5
There is a prism with refractive index equal to √2 and the refracting angle equal to 30°. One of the refracting surface of the prism is polished. A beam of monochromatic light will retrace its path if its angle of incidence over the refracting surface of the prism is .. [ CBSE-PMT 1992]
  • a) 0°
  • b) 30°
  • c) 45°
  • d) 60°
Q.6
The refractive index of the material of prism is √2 and its refracting angle is 30°. One of the refracting angle is 30°. One of the refracting surfaces of the prism is made a mirror inwards. A beam of monochromatic light enters the prism from the mirrored surface it its angle of incidence of the prism is [ CBSE-PMT 2004]
  • a)30°
  • b) 45°
  • c)60°
  • d)0°
Q.7
A beam of light composed of red and green rays is incident obliquely at a point on the face of rectangular glass slab. When coming out on the opposite parallel face, the red and green rays emerge from.. [ CBSE-PMT 2004]
  • a) one point propagating in the same direction
  • b) two points propagating in two different non-parallel directions
  • c)two points propagating in two different parallel directions
  • d)one point propagating in two different directions.
Q.8
The radius of curvature of thin plano-convex lens is 10cm and the refractive index is 1.If the plane surface is silvered, then it behaves like a concave mirror of focal length.. [ CBSE-PMT 2000]
  • a) 10 cm
  • b) 15 cm
  • c)20 cm
  • d)5 cm
Q.9
One face of a rectangular glass plate 6cm thick is silvered , an object held 8cm in front of the first face from an image 12cm behind the silvered face. The refractive index of the glass is [ CBSE-PMT 1996]
  • a) 0.4
  • b) 0.8
  • c) 1.2
  • d) 1.6
Q.10
The angular resolution of 10cm diameter telescope at a wave length of 5000Å is of order of the [ CBSE-PMT 2005]
  • a)106 rad
  • b) 10-2 rad
  • c)10-4 rad
  • d)10-6 rad
Q.11
Two coherent sources can be obtained by
  • a) Division of wave front only
  • b) Division of amplitude only
  • c)both division of amplitude and wave front
  • d)None of above
Q.12
A luminous object is placed at a distance of 30cm from the convex lens of focal length 20cm. On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature 10cm be placed in order to have an upright image of the object coincident with it? [ CBSE-PMT 1998]
  • a) 12cm
  • b) 30cm
  • c)50cm
  • d)60cm
Q.13
An air bubble in a glass slab ( µ=1.5) is 5 cm when viewed from one face and 2cm deep when viewed from the opposite face. The thickness of the slab is .. [ CBSE-PMT 2000]
  • a) 7.5 cm
  • b) 10.5 cm
  • c) 7 cm
  • d) 10cm
Q.14
A ray is incident at an angle of incidence i on one surface of a prism of small angle A and emerges normally from the opposite surface. If the refractive index of the material of prism is µ, the angle of incidence i is nearly equal to.. [ CBSE-PMT 1989]
  • a)A/µ
  • b) A/ 2µ
  • c)µA
  • d)µA /2
Q.15
Green light of wavelength 5460Å is incident on an air-glass interface. If the refractive index of glass is 1.5, the wave length of light in glass would be ( c=3× 108 ms-1) [ CBSE-PMT 1991]
  • a) 3640Å
  • b) 5460Å
  • c)4861Å
  • d)none of the above
Q.16
Angle of deviation (δ) by a prism, µ is refractive index, A is angle of prism very small then .. [ CBSE-PMT 1994]
  • a) δ=(µ - 1) A
    ch-11_qn-44choice_img_no3.png
  • b) δ=(µ + 1) A
    ch-11_qn-44choice_img_no4.png
  • c)
  • d)
Q.17
The hypermetropia is a.. [ CBSE-PMT 1995]
  • a)short sight defect
  • b) long sighted defect
  • c)bad vision due to to old age
  • d)none of these
Q.18
A lens is placed between a source of light and a wall. It form images of area A1 and A2 on the wall for two different positions. The area of the source of light is ... [ CBSE-PMT 1995]
  • a)
    ch-11_qn-46choice_img_no1.png
  • b)
    ch-11_qn-46choice_img_no2.png
  • c)
    ch-11_qn-46choice_img_no3.png
  • d)
    ch-11_qn-46choice_img_no4.png
Q.19
Two thin lenses of focal lengths f1 and f2 are in contact and coaxial. The power of the combination is .. [ CBSE-PMT 2008]
  • a)
    ch-11_qn-47choice_img_no1.png
  • b)
    ch-11_qn-47choice_img_no2.png
  • c)
    ch-11_qn-47choice_img_no3.png
  • d)
    ch-11_qn-47choice_img_no4.png
Q.20
An electromagnetic radiation of frequency n, wave length λ traveling with velocity V in air enters in glass slab of refractive index µ . The frequency, wavelength and velocity of light in the glass slab will be respectively... [ CBSE-PMT 1997]
  • a) n, λ/µ and v/ µ
  • b) n, 2λ and v/µ
  • c) n/µ , λ/µ and v/ µ
  • d) 2π /µ , λ / µ and v
Q.21
Rainbow is formed due to a combination of [ CBSE-PMT 2000]
  • a)dispersion and total internal reflection
  • b) refraction and absorption
  • c)dispersion and focusing
  • d)refraction and scattering
Q.22
A light ray falls on a rectangular glass slab as shown. The index of refraction of the glass, if total internal reflection is to occur at the vertical face, is
ch-11_que_no-50_img_no1.png
  • a)
    ch-11_qn-50choice_img_no1.png
  • b)
    ch-11_qn-50choice_img_no2.png
  • c)
    ch-11_qn-50choice_img_no3.png
  • d)
    ch-11_qn-50choice_img_no4.png
Q.23
A telescope has an objective lens of 10cm diameter and is situated at a distance of one kilometer from two objects. The minimum distance between these two objects, which can be resolved by the telescope, when the mean wavelength of light is 5000Å, is of the order of .. [ CBSE-PMT 2004]
  • a) 5cm
  • b) 0.5m
  • c)5m
  • d)5mm
Q.24
Plane mirror A and B are kept at an angle of θ with respect to each other. Light falls on A is reflected, then falls on B and is reflected. the emergent ray is opposite to the incident direction. Then the angle θ is equal to [ SCRA 1994]
  • a) 45°
  • b) 30°
  • c) 60°
  • d) 90°
Q.25
When a ray of light enters a glass slab from air [ IIT 1980]
  • a)Its wavelength decreases
  • b) Its wavelength increases
  • c)Its frequency decreases
  • d)neither its wavelength nor its frequency changes
Q.26
A glass prism of refractive index 1.5 is immersed in water ( refractive index 4/3). A light beam incident normally on the face AB is totally reflected to reach on the face BC if ...[IIT 1981]
ch-11_que_no-54_img_no1.png
  • a) sinθ ≥ (8/9)
  • b) (2/3) < sinθ<(8/9)
  • c)sinθ ≤ (2/3)
  • d)sinθ=(8/9)
Q.27
In Young's double-slit experiment, the separation between the slit is halved and the distance between the slits and the screen is doubled. The fringe width is [ IIT 1981]
  • a) unchanged
  • b) halved
  • c)doubled
  • d)quadrupled
Q.28
Two coherent monochromatic light beams of intensity I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are [ IIT 1988]
  • a)5I and I
  • b) 5I and 3I
  • c)9I and I
  • d)9I and 3I
Q.29
Spherical aberration in a thin lens can be reduced by [ IIT 1994]
  • a) using a monochromatic light
  • b) using a doublet combination
  • c)using a circular annular mark over the lens
  • d)increasing the size of the lens
Q.30
A concave mirror of focal length 20cms produces an image twice the size of the object. If the image is real, then the distance of the object from the mirror is
  • a) 20 cm
  • b) 10 cm
  • c) 30 cm
  • d) 60 cm
Q.31
In the phenomenon of interference, energy is
  • a) Destroyed at bright fringe
  • b) created at dark fringes
  • c) conserved , but redistributed
  • d) same at all points
Q.32
A diminished image of an object is to be obtained on a screen 1.0 m from it. This can be achieved by appropriately placing [ IIT 1995]
  • a)a concave mirror of suitable focal length
  • b) a concave mirror of suitable focal length
  • c)a convex lens of focal length less than 0.25 m
  • d)a concave lens of suitable focal length
Q.33
The focal length of the objective and the eye piece of compound microscope microscope are 2.0 cm and 3.0 cm respectively. The distance between the objective and the eye piece is 15.0cm. The final image formed by the eye piece is at infinity. The two lenses are thin. The distance in cm of the object and the image produced by the objective, measured from the objective lens are respectively [ IIT 1995[
  • a) 2.4 and 12.0
  • b) 2.4 and 15.0
  • c)2.0 and 12.0
  • d)2.0 and 3.0
Q.34
Consider Fraunhoffer diffraction pattern obtained with a single slit illuminated at normal incidence. At the angular position of the first diffraction minimum the phase difference ( in radians) between the wavelets from the opposite edges of the slit is [ IIT 1995]
  • a) π/4
  • b) π/2
  • c)2π
  • d)π
Q.35
In an interference arrangement similar to Young's double slit experiment, the slit S1 and S2 are illuminated with coherent microwave sources, each of frequency 106 Hz. The sources are synchronized to have zero phase difference. The slits are separated by a distance d=150.m. The intensity I(θ) is measured as a function of θ is defined as shown. If Io is the maximum intensity, then I(θ) for θ ≤ θ≤ 90 is given by [ IIT 1995]
ch-11_que_no-64_img_no1.png
  • a) I(θ)=Io / 2 for θ=30°
  • b) I(θ)=Io / 4 for θ=90°
  • c) I(θ)=Io for θ=0°
  • d) I(θ) is constant for all the values of θ
Q.36
An eye specialist prescribes spectacles having combination of convex lens of focal length 40cm in contact with a concave lens of focal length 25cm. The power of this lens combination in diopters is [ IIT 1997]
  • a)+1.5
  • b) -1.5
  • c)+6.67
  • d)-6.67
Q.37
A concave lens of glass refractive index 1.5 has both surfaces of same radius of curvature R. On immersion in a medium of refractive index 1.75 it will behave as a [ IIT 1999]
  • a) convergent lens of focal length 3.5R
  • b) convergent lens of focal length 3.0R
  • c)divergent lens of focal length 3.5R
  • d)divergent lens of focal length 3.0R
Q.38
Yellow light is used in a single slit diffraction experiment with slit width of 0.6 mm. If yellow light is replaced by X-ray, then the observed pattern will revel [ IIT 1995]
  • a) that the central maximum is narrower
  • b) more number of fringes
  • c)less number of fringes
  • d)no diffraction pattern
Q.39
A thin slice is cut of a glass cylinder along the plane parallel to axis. The slice is placed on a flat glass plate as shown in figure. The observed interference fringes from this combination shall be [ IIT 1995]
ch-11_que_no-68_img_no1.png
  • a) straight
  • b) circular
  • c) equally spaced
  • d) having fringe spacing which increases as we go outwards
Q.40
A hollow double concave lens is made of very thin transparent material. It can be filled with air or either of two liquids L1 or L2 having refractive indices n1 and n2 respectively ( n2 > n1 > 1). The lens will diverge a parallel beam of light if it is filled with [ IIT 2000]
  • a)air and placed in air
  • b) air and immersed in L1
  • c)L1 and immersed in L2
  • d)L2 and immersed in L1
Q.41
A point source of light B is placed at a distance L in front of the centre of a mirror of width 'd' hung vertically on a wall. A man walks in front of mirror along a line parallel to the mirror at a distance 2L from it as shown in figure. The greatest distance over which he can see the image of the light source in the mirror is [ IIT 2000]
ch-11_que_no-70_img_no1.png
  • a) d / 2
  • b) d
  • c)2d
  • d)3d
Q.42
In an experiment to determine the focal length (f) of a concave mirror by the u-v method, a student places the object pin A on the principal axis at a distance x from the pole P. The student looks at the pin and its inverted images from a distance keeping his /her eye in line with PA. When the student shifts his/her eye towards left, the image appears to the right of the object pin. Then [ IIT 2007]
  • a) x < f
  • b) f < x < 2f
  • c) x=2f
  • d) x > 2f
Q.43
A divergent beam of light from a point source S having divergent angle α, falls symmetrically on a glass slab as shown. The angle of incidence of the two extreme rays are equal. If the thickness of the glass slab is t and the refractive index n, then the divergence angle of the emergent beam is [ IIT 2000]
ch-11_que_no-71_img_no1.png
  • a) zero
  • b) α
  • d)2sin-1( 1/n)
  • c)sin⁻¹( 1/n)
Q.44
In a double slit experiment instead of taking slits of equal width, one slit is made twice as wide as the other. Then, in the interference pattern [ IIT 2000]
  • a)the intensities of both the maxima and the minima increase
  • b) the intensity of the maxima increases and the minima has zero intensity
  • c)the intensity of the maxima decreases and that of the minima increases
  • d)the intensity of the maxima decreases and the minima has zero intensity
Q.45
In a compound microscope, the intermediate image is [ IIT 2005]
  • a) virtual, erect and magnified
  • b) real, erect and magnified
  • c)real, inverted and magnified
  • d)virtual, erect and reduced
Q.46
Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. the phase difference between the beams is π/2 at point A and π at point B. Then the difference between the resultant intensities at A and B is [ IIT 2001]
  • a) 2I
  • b) 4I
  • c)5I
  • d)7I
Q.47
In a Young's double slit experiment, 12 fringes are observed to be formed in a certain segment of the screen when light of wave length 600nm is used. If the ave length of light is changed to 400 nm, number of fringes observed in the same segment of the screen is given by [ IIT 2001]
  • a) 12
  • b) 18
  • c) 24
  • d) 30
Q.48
A ray of light passes through four transparent media with refractive indices n1, n2, n3 and n4 as shown in the figure. the surface of all media are parallel. if the emergent ray CD is parallel to the incident ray AB, we must have [ IIT 2001]
ch-11_que_no-77_img_no1.png
  • c)n3=n4
  • b) n2=n3
  • a)n₁=n₂
  • d)n₄=n₁
Q.49
A given ray of light suffers minimum deviation in an equilateral prism P. Additional prism Q and R of identical shape and of the same material as P are now added as shown in the figure. The will now suffer [ IIT 2001]
ch-11_que_no-78_img_no1.png
  • a) greater deviation
  • b) no deviation
  • c)same deviation as before
  • d)total internal reflection
Q.50
An observer can see through a pin-hole the top end of a thin rod of height h, placed as shown in figure. The beaker height is 3h and its radius h. When the beaker is filled with a liquid up to a height 2h, he can see the lower end of the rod. Then the refractive index of the liquid is [ IIT 2002]
ch-11_que_no-79_img_no1.png
  • a)5/2
  • b)√(5/2)
  • c)√(3/2)
  • d)3/2
0 h : 0 m : 1 s