Question

A teacher gives a convex lens and a concave mirror of foal length 20 cm each to his student and asks him to find their focal length by obtaining the image of a distant object. The student uses a distant tree as the object and obtains it's sharp image,one by one,on a screen. The distances d1 and d2 between the lens/mirror and the screen in the two cases and the nature of their respective sharp images are likely to be. Give reason for your answer

Answer 1

Answer is (20cm , 20cm ) INVERTED.

This is because when the object is At infinity, the image is formed At focus.

Therefore, image distance = focal length.

Given,focal length = 20cm

Therefore,image distance = 20cm.

Moreover, when object is at infinity, the image is of point sized and inverted.

Thank You.

Answer 2

Answer:

D1&D2 are inverted and has focal length 20cm each

Step-by-step

they are inverted image since convex lens and concave mirror shows inverted image