09. Ray Optics and Optical Instruments
Question 1.
Which of-the following is not a property of Answer: (c) π
light?
(a) It can travel through vacuum Question 5. Which of the following cannot be
(b) It has a finite speed polarised?
(c) It requires a material medium for its (a) radiowaves
propagation (b) transverse waves
(d) It involve transportation energy (c) sound waves
(d) X-rays
Answer: (c) It requires a material medium for
its propagation Answer: (c) sound waves
Question 2. Two points P and q are situated at Question 6. Light year is the unit of:
the same distance from a source of light but on (a) distance
opposite sides. The plane difference between (b) time
the light waves passing through P and q will (c) intensity of light
be: (d) None of these
(a) n
(b) 2n Answer: (a) distance
(c) π2
(d) zero
Question 7. If a mirror is approaching you at a
speed of 10 ms^1, the speed with which your
image approach you is:
Answer: (d) zero (a) 10 ms-1
(b) 5 ms-1
Question 3. The phase difference between the (c) 20 ms-1
electric and the magnetic field vectors in (d) 15 ms-1
electromagnetic waves is
(a) π4 Answer: (c) 20 ms-1
(b) π2
(c) π
(d) zero Question 8. The refractive indices (R.I.) of
glass and water with respect to air are 3/2 and
4/3 respectively. The R.I. of glass w.r. to w ater
is:
Answer: (d) zero (a) 8/9
(b) 9/8
Question 4. A ray of light travelling in air is (c) 7/6
incident of a glass slab. The ray gets partly (d) 2
reflected and partly refracted. The phase
difference between the reflected and the Answer: (b) 9/8
refracted waves is :
(a) π2
(b) π4
(c) π
(d) zero
, Question 9. The angle of minimum deviation Question 13. A thin glass (RI = 32) lens has
for an equilateral glass prism is 30°. Refractive optical power of – 5D in air. Its optical power in
index of the prism is: a liquid medium with RI = 1.6 will be:
(a) 1√3 (a) -2.5 D
(b) √2 (b) 25 D
(c) 1 (c) -ID
(d) can’t be determined (d) 0.625 D
Answer: (b) √2 Answer: (d) 0.625 D
Question 14. On reflection from a denser
medium, a light wave suffers a phase
difference of:
Question 10. A beam of light is incident at 60° (a) π
to a plane surface. The reflected and refracted (b) π2
rays are perpendicular to each other. What is (c) π4
the R.I. of the surface: (d) 2π
(a) 1√3
(b) √3
(c) 13 Answer: (a) π
(d) 3
Question 15. The branch of optics dealing with
the formation of images using the concept of
Answer: (b) √3 straight line propagation of light is called:
(a) geometrical optics
Question 11. A concave mirror of focal length f (b) physical optics
produces an image n times the size of the (c) corpuscular optics
object. If the image is real then the distance of (d) quantum optics
the object is:
(a) (n – 1) f Answer: (d) quantum optics
(b) (n + 1) f
(c) (n+1n)f
(d) (n−1n)f Question 16. When light travels from one
medium to another, which of the following does
Answer: (c) (n+1n)f not change?
(a) frequency
(b) refractive index
(c) velocity
Question 12. A convergent lens will become (d) wavelength
less convergent in :
(a) oil
(b) water Answer: (a) frequency
(c) both of (a) and (b)
(d) none of these Question 17. Two lens of power -15 D and +5
D are placed in contact co-axially. The focal
Answer: (b) water length of equivalent lens is:
(a) -10 cm
(b) -20 cm
Question 1.
Which of-the following is not a property of Answer: (c) π
light?
(a) It can travel through vacuum Question 5. Which of the following cannot be
(b) It has a finite speed polarised?
(c) It requires a material medium for its (a) radiowaves
propagation (b) transverse waves
(d) It involve transportation energy (c) sound waves
(d) X-rays
Answer: (c) It requires a material medium for
its propagation Answer: (c) sound waves
Question 2. Two points P and q are situated at Question 6. Light year is the unit of:
the same distance from a source of light but on (a) distance
opposite sides. The plane difference between (b) time
the light waves passing through P and q will (c) intensity of light
be: (d) None of these
(a) n
(b) 2n Answer: (a) distance
(c) π2
(d) zero
Question 7. If a mirror is approaching you at a
speed of 10 ms^1, the speed with which your
image approach you is:
Answer: (d) zero (a) 10 ms-1
(b) 5 ms-1
Question 3. The phase difference between the (c) 20 ms-1
electric and the magnetic field vectors in (d) 15 ms-1
electromagnetic waves is
(a) π4 Answer: (c) 20 ms-1
(b) π2
(c) π
(d) zero Question 8. The refractive indices (R.I.) of
glass and water with respect to air are 3/2 and
4/3 respectively. The R.I. of glass w.r. to w ater
is:
Answer: (d) zero (a) 8/9
(b) 9/8
Question 4. A ray of light travelling in air is (c) 7/6
incident of a glass slab. The ray gets partly (d) 2
reflected and partly refracted. The phase
difference between the reflected and the Answer: (b) 9/8
refracted waves is :
(a) π2
(b) π4
(c) π
(d) zero
, Question 9. The angle of minimum deviation Question 13. A thin glass (RI = 32) lens has
for an equilateral glass prism is 30°. Refractive optical power of – 5D in air. Its optical power in
index of the prism is: a liquid medium with RI = 1.6 will be:
(a) 1√3 (a) -2.5 D
(b) √2 (b) 25 D
(c) 1 (c) -ID
(d) can’t be determined (d) 0.625 D
Answer: (b) √2 Answer: (d) 0.625 D
Question 14. On reflection from a denser
medium, a light wave suffers a phase
difference of:
Question 10. A beam of light is incident at 60° (a) π
to a plane surface. The reflected and refracted (b) π2
rays are perpendicular to each other. What is (c) π4
the R.I. of the surface: (d) 2π
(a) 1√3
(b) √3
(c) 13 Answer: (a) π
(d) 3
Question 15. The branch of optics dealing with
the formation of images using the concept of
Answer: (b) √3 straight line propagation of light is called:
(a) geometrical optics
Question 11. A concave mirror of focal length f (b) physical optics
produces an image n times the size of the (c) corpuscular optics
object. If the image is real then the distance of (d) quantum optics
the object is:
(a) (n – 1) f Answer: (d) quantum optics
(b) (n + 1) f
(c) (n+1n)f
(d) (n−1n)f Question 16. When light travels from one
medium to another, which of the following does
Answer: (c) (n+1n)f not change?
(a) frequency
(b) refractive index
(c) velocity
Question 12. A convergent lens will become (d) wavelength
less convergent in :
(a) oil
(b) water Answer: (a) frequency
(c) both of (a) and (b)
(d) none of these Question 17. Two lens of power -15 D and +5
D are placed in contact co-axially. The focal
Answer: (b) water length of equivalent lens is:
(a) -10 cm
(b) -20 cm
