Question

1. You place an object 63 cm in front of a converging lens, with a 40 cm focal length.

Find the location of the image.

Find the magnification.

Is the image real or virtual?

2. An object is placed to the left of a converging lens of focal length f = 30 cm, such that the object-to-image distance is 5 cm. Find the magnification.

Answer 1

1.

109.6 cm , - 1.74 , real

2.

1.5

Step-by-step explanation:

1.

d₀ = object distance = 63 cm

f = focal length of the lens = 40 cm

d = image distance = ?

using the lens equation

`(1)/(f) = (1)/(d_(o)) + (1)/(d)`

`(1)/(40) = (1)/(63) + (1)/(d)`

d = 109.6 cm

magnification is given as

`m = (-d)/(d_(o))`

`m = (-109.6)/(63)`

m = - 1.74

The image is real

2

d₀ = object distance = a

d = image distance = - (a + 5)

f = focal length of lens = 30 cm

using the lens equation

`(1)/(f) = (1)/(d_(o)) + (1)/(d)`

`(1)/(30) = (1)/(a) + (1)/(- (a + 5))`

a = 10

magnification is given as

`m = (-d)/(d_(o))`

`m = (- (- (a +5)))/(a)`

`m = ((5 + 10))/(10)`

m = 1.5