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WorksheetsLIGHT REVISION
Total questions: 12
Worksheet time: 12mins
A student obtains a blurred image of a distant obʼnect on a screen using a convex lens. To obtain a distinct image on the screen he should move the lens:
away from the screen
towards the screen
to a position very far away from the screen
either towards or away from the screen depending upon the position of the object
The refractive index of four substance P, Q, R and S are 1.30, 1.33, 1.44 and 1.31 respectively. The speed of light is the maximum in the substance:
P
Q
R
S
You are given water, mustard oil, glycerin and kerosene. In which of these media, a ray of light incident from air obliquely at the same angle would bend the most? (Refractive index of water = 1.33, mustard oil =1.46, Glycerin = 1.473, kerosene = 1.44)
water
mustard oil
kerosene
glycerin
Assertion (A) : Power of a concave lens is negative.
Reason (R) : A concave lens has a virtual focus
a) Both (A) and (R) are true and (R) is the correct explanation of the (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of the (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.
A teacher sets up the stand carrying a convex lens of focal length 15 cm at 42.7 cm mark on the optical bench. He asks four students A, B, C and D to suggest the position of screen on the optical bench so that a distinct image of a distant tree is obtained almost immediately on it. Which student is correct if the positions suggested by the students were as:
12.7 cm
29.7 cm
57.7 cm
72.7 cm
A ray of light passes from medium A to medium B. No bending of light occurs if the ray of light hits the boundary of medium B at an angle of:
90 degree
0 degree
45 degree
180 degree
Assertion: Keeping a point object fixed, if a plane mirror is moved, the position of its image does not move.
Reason: In a plane mirror, distance between the object and mirror is always equal to the distance between the image and the mirror.
(a) Both (A) and (R) are true and (R) is the correct explanation of the (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of the (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.
Focal length of a plane mirror is
zero
25 cm
-100 cm
infinity
A spherical mirror and a thin spherical lens each have a focal length -15 cm. Mirror and lens are likely to be:
(a) Both concave
(b)Both convex
(c) Mirror is concave and lens is convex
(d) Mirror is convex and lens is concave
A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is :
(a) -30 cm
(b) -20 cm
(c) 40 cm
(d) -60 cm
The linear magnification produced by a spherical mirror is +3. Which of the following is correct?
Image formed is real and inverted
Convex mirror is used
Image formed is virtual and enlarged
Image formed is in front of the mirror
Image formed by a mirror having a focal length of 20 cm, reduced to 1/3rd of its size, is formed behind the mirror. At what distance the object has been placed from the mirror?
20 cm
40 cm
10 cm
30 cm
