Question

A student focuses the image of a candle flame, placed at about 2 m from a convex lens of focal length 10 cm, on a screen. After that he moves gradually the flame towards the lens and each time focuses its image on the screen.
A) In which direction does he move the lens to focus the flame on screen ?
B) What happens to the size of the image of the flame formed on the screen ?
C) What difference is seen in the intensity (brightness) of the image on the screen ?
D) What is seen on the screen when the flame is very close (at about 5 cm) to the lens ?

Answer 1

A.. he should move the lens towards the flame
B...it increases
C...increases (nt sure)
D...bcoz of virtual and erect image...image will not be obtained on the screen.

Answer 2

Hope This is helpful for You

a. He should move lens away from screen because as object distance decreases image will go away from the focus.

b. Size of image will increase as the object is moved towards lens.

c. As image is magnifying intensity of flame decreases.

d. No will be formed on screen as it will form virtual image the the case.