Optic 11 Class 9.Chapter Physics Exercise (Science) Questions Answer Maharashtra Board 2022
Channel: MB Class
Date: 2021-03-20

Optic 11 Class 9.Chapter Physics Exercise (Science) Questions Answer Maharashtra Board
Exercise
1. Choose the correct option 
i. As per recent understanding light consists 
of 
(A) rays 
 (B) waves 
 (C) corpuscles
 (D) photons obeying the rules of waves
ii. Consider optically denser lenses P, Q, 
R and S drawn below. According to 
Cartesian sign convention which of these 
have positive focal length?
 
 (A) Only P
(B) Only P and Q
 (C) Only P and R 
 (D) Only Q and S
iii. Two plane mirrors are inclined at angle 
400
 between them. Number of images 
seen of a tiny object kept between them is
(A) Only 8 (B) Only 9
 (C) 8 or 9 (D) 9 or 10
iv. A concave mirror of curvature 40 cm, 
used for shaving purpose produces image 
of double size as that of the object. Object 
distance must be 
(A) 10 cm only 
(B) 20 cm only 
 (C) 30 cm only 
(D) 10 cm or 30 cm
Exercises
Exercises
v. Which of the following aberrations will 
NOT occur for spherical mirrors?
(A) Chromatic aberration 
 (B) Coma
 (C) Distortion
 (D) Spherical aberration
vi. There are different fish, monkeys and 
water on the habitable planet of the star 
Proxima b. A fish swimming underwater 
feels that there is a monkey at 2.5 m on the 
top of a tree. The same monkey feels that 
the fish is 1.6 m below the water surface. 
Interestingly, height of the tree and the 
depth at which the fish is swimming are 
exactly same. Refractive index of that 
water must be
(A) 6/5 (B) 5/4 
 (C) 4/3 (D) 7/5
vii. Consider following phenomena/
applications: P) Mirage, Q) rainbow, 
R) Optical fibre and S) glittering of a 
diamond. Total internal reflection is 
involved in
(A) Only R and S (B) Only R 
 (C) Only P, R and S (D) all the four
viii.A student uses spectacles of number -2 for 
seeing distant objects. Commonly used 
lenses for her/his spectacles are
 (A) bi-concave 
 (B) double concave
 (C) concavo-convex
 (D) convexo-concaveix. A spherical marble of refractive index 
1.5 and curvature 1.5 cm, contains a tiny 
air bubble at its centre. Where will it 
appear when seen from outside?
(A) 1 cm inside (B) at the centre
(C) 5/3 cm inside (D) 2 cm inside
x. Select the WRONG statement.
(A) Smaller angle of prism is 
recommended for greater angular 
dispersion.
(B) Right angled isosceles glass prism is 
 commonly used for total internal 
reflection.
(C) Angle of deviation is practically 
constant for thin prisms.
(D) For emergent ray to be possible from 
 the second refracting surface, certain 
 minimum angle of incidence is 
 necessary from the first surface.
xi. Angles of deviation for extreme colours 
are given for different prisms. Select the 
one having maximum dispersive power 
of its material.
 (A) 7°, 10° (B) 8°, 11° 
(C) 12°, 16° (D) 10°, 14°
xii. Which of the following is not involved in 
formation of a rainbow?
 (A) refraction
 (B) angular dispersion
 (C) angular deviation
 (D) total internal reflection
xiii. Consider following statements regarding 
a simple microscope:
(P) It allows us to keep the object within 
the least distance of distant vision.
(Q) Image appears to be biggest if the 
object is at the focus.
(R) It is simply a convex lens.
(A) Only (P) is correct 
 (B) Only (P) and (Q) are correct
(C) Only (Q) and (R) are correct 
(D) Only (P) and (R) are correct
2. Answer the following questions.
i) As per recent development, what is the 
nature of light? Wave optics and particle 
nature of light are used to explain which 
phenomena of light, respectively?
ii) Which phenomena can be satisfactorily 
explained using ray optics? State the 
assumptions on which ray optics is based.
iii) What is focal power of a spherical mirror 
or of a lens? What may be the reason for 
using P
f = 1
 as its expression?
iv) At which positions of the objects do 
spherical mirrors produce (i) diminished 
image, (ii) magnified image?
v) State the restrictions for having images 
produced by spherical mirrors to be 
appreciably clear. 
vi) Explain spherical aberration for spherical 
mirrors. How can it be minimized? Can it 
be eliminated by some curved mirrors?
vii) Define absolute refractive index and 
relative refractive index. Explain in brief, 
with an illustration for each.
viii) Explain ‘mirage’ as an illustration of 
refraction. 
ix) Under what conditions is total internal 
reflection possible? Explain it with a 
suitable example. Define critical angle of 
incidence and obtain an expression for it.
x) Describe construction and working of 
an optical fibre. What are the advantages 
of optical fibre communication over 
electronic communication?
xi) Why is a prism binoculars preferred 
over traditional binoculars? Describe its 
working in brief.
xii) A spherical surface separates two 
transparent media. Derive an expression 
that relates object and image distances 
with the radius of curvature for a point 
object. Clearly state the