Question

If a number of images of a candle flame are seen in a thick mirror, the
(A) The first image is the brightest
(B) The second image is the brightest
(C ) The last image is the brightest
(D) The image are equally bright

Answer 1

Hint: In the case of a thick mirror two processes are taking place. That is, the first one is reflection and the second one is refraction. The back surface of the thick mirror is silvered hence the light that strikes the silvered surface will appear to the brightest light among the others. Thus the reflected light and images formed due to multiple reflection appear to be dimmer.

Complete answer:
In case of a thick mirror its front surface reflects as well as refracts light incident on it. Due to the reflection at the surface of the mirror, the first image is formed. That will be a dim light since it is a reflected light. And the refracted light strikes on a silvered surface and gets reflected, the image thus formed will appear to be bright. The rest of the images are formed by continuous reflection and refraction. That is, by multiple reflections. Thus these images will be very dim.

Therefore, option (B) is correct.

Note:
The front surface of a thick mirror is usually a reflecting surface. The light gets reflected when it is incident on the front surface of the thick mirror. That will be a dim light since it is a reflected light. And the refracted light strikes on a silvered surface and gets reflected, the image thus formed will appear to be bright. The rest of the images are formed by continuous reflection and refraction. That is, by multiple reflections. Thus these images will be very dim.