Question

Assertion: When an object is placed between two plane parallel mirrors, then all the images found are of equal intensity.
Reason: In the case of plane parallel mirrors, only two images are possible.
A) If both assertion and reason are true and reason is the correct explanation of assertion.
B) If both assertion and reason are true but reason is not the correct explanation of assertion.
C) If the assertion is true but the reason is false.
D) If assertion and reason both are false.

Answer 1

Hint: In a plane mirror, the image formed by the object is formed at a distance equal to the distance of the object from the mirror. The image is also erect and has the same dimensions as those of the object.

Complete step by step answer
When an object is placed between two plane parallel mirrors, then the image of the object will be formed in both the mirrors on both sides of the object. These images will then act as objects for the opposite mirrors and form another image. In this way, an infinite number of images will be formed on both sides of the object. Since a plane mirror forms an image of equal intensity in every reflection, all the images formed will be of equal intensity. So, the assertion is correct.
As we discussed above, if the two plane mirrors are across each other, an infinite number of images will be formed in the two mirrors. So, the reason is incorrect and it is also not the correct explanation of the assertion stamen.
So, the correct choice is option (D).

Note
For an infinite number of images, the two plane mirrors must be completely parallel to each other. Otherwise, if one of the mirrors is slightly tilted, the images formed will slightly tilt and deform in one direction and a finite number of images will be formed. In any case, the intensity of all the images will remain constant so the assertion statement will remain to be true while the reason will be false.