Question

For finding the focal length of a concave mirror, where do we keep the object ?

Answer 1

the object should be kept at infinity
because the rays coming from infinity will converge to meet at the focus .

Answer 2

ANSWER:-----

To find the focal length of a concave mirror, the large sized object is placed at infinity or a very far place. The position of the image formed will be at focus of the mirror and is formed on the screen. The nature of the image formed will be: Real and inverted.

hope it helps:---

T!—!ANKS!!!