Question

Focal length kab negative likhni h ya positive ye kese pta chlta and baaki chizze bhi like hight, object vgyara​

Answer 1

Answer:

Explanation:

Bro object ka mirror ya phir lens se distance humesha negative main rehata hain...jise u bolte hain

I had sent ur answer in respect to spherical lenses and spherical mirrors respectively in this f represent focal point...

U represent object distance.

And v represent image distance