Question

a 2cm high object is placed 4.2cm to the left of a converging lens of focal length 7.6cm. find the position and height of the final image. is the image inverted or upright? is the image real or virtual

Answer 1

The position of the image is 2.71 cm and the image is inverted and real.

How to calculate the position of the image?

The position of the image is calculated by applying the following formula as follows;

1/f = 1/v + 1/u

where;

• f is the focal length
• v is the image distance
• u is the object distance

The given parameters include;

object height, h = 2 cm

object distance, u = - 4.2 cm

focal length of the lens = 7.6 cm

The position of the image is calculated as;

1/7.6 = 1/v - (1/4.2)

1/v = 1/7.6 + 1/4.2

1/v = 0.3697

v = 1/0.3697

v = 2.71 cm

so the image is inverted and real.

The magnification of the lens is calculated as;

m = v / u

m = 2.71 / 4.2

m = 0.65