Question

Problem 7.17 Where must a pin be placed before a concave mirror of radius of curvature 300mm to form an image 400mm from the mirror which is a. real b. virtual? Answer: (a) 240mm (b) 109.1mm min

Answer 1

ONly one question can be posted as per HOMEWORKLIB RULES

7.17

a_

focal length

f=R/2 =300/2 =150 mm

From thin lens formula

1/f = 1/d_i + 1/d_o

1/150 =1/400 +1/d_o

d_o = 240 mm

b)

f=-150 mm

=>-1/150 =1/400 +1/d_o

d_o =-109.1 mm

7.18

a)

focal legth

f=-R/2 =-1.2/2 =-0.6 m

From thin lens formula

1/f =1/d_i + 1/d_o

-1/0.6 =1/13.5 +1/d_i

d_i =-0.574 m =-0.57 m

b)

SInce Magnification

M=-d_i/d_o = h_i/h_o

-(-0.57)/13.5 =h_i/1.5

h_i = 0.0633 m =63.3 mm