66) When distance between object and screen s more than 4 times the focal length, in many positions of the convex lens, images is sharp
A) 1
B) 2
C) 3
D) 4
67) If a light ray passing through centre of curvature C. of a mirror is incident on the mirror, the reflected ray’s path is [b, c]
A) Through focus (F)
B) Through centre of curvature C.
C) Retraces the path And Through centre of curvature C.
D) Through any point
68) If magnification is equal to one, it means
A) Image is smaller than object
B) Image is larger than object
C) Image is of the same size as that of object
D) Image is point size
69) An object is placed at a certain distance on the principal axis of a concave mirror. If the image distance (v) is 30 cm and radius of curvature (R) of the mirror is 20 cm, find the object distance (u)
A) 10 cm
B) 15 cm
C) 30 cm
D) 7.5 cm
Explanation:Use mirror formula:
Answer: 15 cm
70) Which part of our eye is responsible for image formation
A) Cornea
B) Crystalline lens
C) Aqueous humor
D) Iris