Question

In the following table nature, size and position of images formed by concave mirrors are given, which one is wrong?

• A) Between P and F Behind the mirror virtual and erect magnified.

• (A) Beyond C between C and F real and inverted diminished.

(B) Between C and F beyond C real and inverted diminished.

(C) At infinity at focus real and inverted Highly diminished

• A. (A)

B. (B)

C. (C)

D. (D)

Answer 1

Hint:In this question, use the concept of the law of reflection to draw each case and try to locate the image for the given position of the object and obtain the position nature and the size of the object to obtain the correct option.

Complete step by step solution:
If we solve it case wise then we get a clear picture of which option is wrong, so we will take first case as,

Case 1- When the object is placed between P and F,

Here in this case the object is sending light rays towards the mirror and we are considering two light rays, one passing through the pole and getting reflected and the other as shown. If we produce the light rays on the back of the mirror, we get the virtual image which is more in height than the object. Hence the image is virtual and erect and is magnified in nature.

Case 2- When object is beyond Center of Curvature,

When the object is kept beyond the center of curvature then considering one parallel light ray reflecting and passing through the focus and the other one passing through C, and getting reflected as it is, we get the point of intersection of these reflected rays and hence the image is formed. The image formed is inverted, small in size and real as it is formed on the same side of the mirror. Hence option B is also correct.

Case 3 – When the object is placed between C and F,

Here in this case when the object is placed between C and F, then considering one parallel line which after reflection passes through focus and considering another one passing through C itself; we find that the object formed is inverted in nature and formed beyond C. The size of the image is magnified. But in options it is given as diminished, hence option C is incorrect.

Case 4 - When object is kept at infinity,

Following the same steps as in above cases we find that the image formed here is exactly at the focal point. Hence the image is highly diminished and real and inverted in nature.

Thus, the correct option is C.

Note:As we know that the parallel rays of light after reflection of light get reflected towards the focus and if the ray of light passes through the focus of the mirror after reflection it gets parallel to the axis of the mirror. If the ray of light incident on the center of the mirror gets reflected back.