Question

Pls it's urgent ...
Use the lens equation deduce algebraically that an object placed within the focus of a convex lens produces a virtual
and enlarged image

Answer 1

let's get the lens formula

1/ v = 1/f + 1/ u

now let's get them in a standard form

1/v - 1/ u = 1/f

u - v / u x v. ....Equating the denominator

(u - v ) f = u x v

Hence if the object is placed within the focus of a convex lens It will be always negative

As image distance is Subtracted by object distance hence we get a negative number

And if that negative number is multiplied by f ....given

It will produce a Negative image means an image that is in front of the lens that means a virtual and erected one ....