Question

A student performs an activity where he uses a lamp and projects its image on a screen as shown in the image.


He kept on changing the distance between the lamp and the mirror for various positions. He notices that the image formed on the screen disappears when the lamp is held close to the mirror. What explains the disappearance of the image on the screen? Where will be the image formed?

I will mark you as brainlist if answered​

Answer 1

Answer:

1 + u1 = f1 ⇒ −801 + −201 = f1 ⇒ f= −(20+80)20×80 = 100−1600 =−16 cmi) Since , f is negative , the mirror is concave mirrorii) Magnification = u−v = −20−(−80) = 4 iii) From fig distance between object and image is

From fig distance between object and image is 60 cm

Answer 2

Answer:

The disappearance of the image on the screen can be explained by the following details -

• When the object is placed too close to the mirror that is between the focus and the pole of the mirror.
• The light rays reflected by the object do not intersect in front of the mirror, therefore we extend the diverged rays at the back of the mirror and that is where the image is formed.
• The image formed is erect, virtual, and enlarged.
• Since the image is formed behind the mirror the image formed on the screen disappears.