Question

.at which distance the image of candle can be observed of it is kept at the distance of 4 feet

Answer 1

I assume the mirror is a plane mirror.

A plane mirror forms virtual erect images. The reason is that the light rays from the object are incident on the mirror and get reflected away. The appear to diverge from a virtual image behind the mirror.

From geometry of reflection we can find that the virtual images formed by plane mirrors are at the same distance behind the mirror as the object is from the mirror.  Also the size of the image is exactly same as that of the object. That is magnification is 1.

Candle distance from mirror = 4 feet.
So virtual image is 4 feet behind the mirror.

So the mirror image is 8 feet away from the candle and is on the other side of the mirror. Size of image is equal to that of the object, ie., candle itself.

Answer 2

Answer:

which distance the image of candle can be observed of it is kept at the distance of 4 feet

For plane mirrors, the object distance (often represented by the symbol do) is equal to the image distance (often represented by the symbol di). That is, the image is the same distance behind the mirror as the object is in front of the mirror.

For example, if we stand at a distance of 2 meters from a plane mirror, we must focus at a location 2 meters behind the mirror in order to view our image.

In this case, the distance between the object and its image formed by a plane mirror appears to be 24 cm. So, the object distance will be 24 / 2 = 12 cm.

Hence, the distance between the mirror and the object is 12 cm.