Question

what is lens formula? what are the symbols used to describe it. what are sign convention used

Answer 1

Lens formula ---- 1/v _1/u =1/f. Relationship between image, object and focal length of a lens.
v is image distance. u is object distance. f is focal length.
Sign convention for lens---
u is always negative.
v depends ---- if on the left side, negative. If on the right side, positive.
Real and inverted images are negative.
Virtual and erect images are positive.

Hope this helps. Mark brainliest.

Answer 2

                         Note :

• f = focal length

• v = distance of image .

• u = distance of object .

Lens formula :

1 / f = 1 / v - 1 / u

Concave lens :

f = negative

u = negative

v =  negative

Convex lens

f = positive

u = negative

v = positive for real image ,

v = negative for virtual image .

The optical centre is chosen as the origin of the coordinate system.

With respect to optical centre :

The part which are above are positive, below negative.

The part which are right are positive while left is negative.

This is just like the normal x-axis and y-axis in the co-ordinate system .