Question

An object is placed at a distance of 60cm from a concave lens of focal length 30cm.
1) Use lens formula to find the distance of the image from the lens
2) List four characteristics of the image (nature,position,size,erect/inverted formed by the lens in this case.
3)Draw ray diagram to justify your answer of part (2)

Answer 1

Explanation:

Given that,

Object distance = -60 cm

Focal length = 30 cm

(a). We need to calculate the image distance

Using formula of focal length

$\dfrac{1}{v}+\dfrac{1}{u}=\dfrac{1}{f}$

$\dfrac{1}{v}=\dfrac{1}{f}-\dfrac{1}{u}$

Put the value into the formula

$\dfrac{1}{v}=\dfrac{1}{-30}+\dfrac{1}{60}$

$\dfrac{1}{v}=-\dfrac{1}{60}$

$v =-60\ cm$

The image is formed at 60 cm distance from the lens.

The size of the image is equal to the size of object.

(b). We need to calculate the magnification

Using formula of magnification

$m=-\dfrac{v}{u}$

Put the value into the formula

$m=-\dfrac{-60}{-60}$

$m=-1$

The nature of the image is real and inverted.

Hence, This is the required solution.

Answer 2

Answer:

Hope u will satisfied with my answer

Good morning dear