Question

(a) In front of a spherical concave mirror of radius E. 31 cm, you position an object of height F. 1.7 cm somewhere along the principal axis. The resultant image has a height of G. 1.4 cm. How far from the mirror is the object located? (10 points) Answer: ____________.__ cm

(b)In front of a spherical convex mirror of radius E. 31 cm, you position an object of height F. 1.7 cm somewhere along the principal axis. The resultant image has a height of G. 1.4 cm. How far from the mirror is the object located? (10 points) Answer: ____________.__ cm

(c) On one side of a converging lens of focal length H. 16 cm, you position an object of height I. 2.7 cm somewhere along the principal axis. The resultant image has a height of J. 1.0 cm. How far from the lens is the object located? (10 points) Answer: ____________.__ cm

(d) On one side of a diverging lens of focal length H. 16 cm, you position an object of height I. 2.7 cm somewhere along the principal axis. The resultant image has a height of J. 1.0 cm. How far from the lens is the object located? (10 points) Answer: ____________.__ cm

Answer 1

For mirrors as well as lenses,
magnification M = F / ( F - d_o ) , F being focal length and d_o being distance of object from mirror or lens.
m is +ve for erect image and -ve for inverted image.

a) If Concave mirror forms small image, it is real and inverted image, hence
M = -1.4/1.7, F is positive and equal to R/2. So F = 16.5
hence - 14/17 = 16.5 / (16.5 - d_o )
d_o = 36.5 cm

b) Convex mirror forms small and erect image of all real objects , hence
M = 1.4/1.7, F is negative and equal to R/2. So F = -16.5
hence 14/17 = -16.5 / (-16.5 - d_o )
d_o = 3.54 cm

c) If Converging lens forms small image, it is real and inverted image, hence
M = -1.0/2.7, F is positive , So F = 16
hence - 1/2.7 = 16 / (16 - d_o )
d_o = 59.2 cm

d) Diverging lens forms small and erect image of all real objects , hence
M = 1.0/2.7, F is negative, So F = -16
hence 1/2.7 = -16 / (-16 - d_o )
d_o = 27.2 cm