An index pin of height 3 cm is kept at a distance of 15 cm from a convex lens of focal length 10 cm. The image is obtained on a screen placed on the other side of the lens. What is the height and nature of the image ?

Options

A. 3 cm, erect
B. 6 cm, erect
C. 6 cm, inverted
D. 1.5 cm, inverted

Answer

C

Explanation

For the convex lens, `f=+10 cm, u= -15 cm`
`because (1)/(v)-(1)/(u)=(1)/(f)`
`therefore (1)/(v)=(1)/(f)+(1)/(u)`
`=(1)/(10)-(1)/(15)=(15-10)/(150) =(5)/(150)=(1)/(30)`
`therefore v=30 cm" " `(`therefore` it is a real image)
`therefore (I)/(o)=(v)/(u)=(30)/(15)=2 `
`therefore ` Height of the image `=2xx3=6 cm`
and as it is a real image, it must be inverted .