Question

1 student using a lens of focal length + 50 cm and another of - 50 cm. State the nature of each lens and find their powers. Which of the two lenses will always given virtual erect and diminished image irrespective of the image.​

Answer 1

Answer:

Step-by-step explanation:

focal length +50 of a lens tells that it is convex lens as its focal length is in plus......its power ,p=1/f(focal length)

p=1/+50    =+0.02 dioptres

the minus sign of another focal length tells that it is concave lens.....its power,p=1/f

p=1/-50    =-0.02 dioptres.

Answer 2

As we know that focal length is negative in concave lens so it is a concave lens.

100cm/f. = P

100/ -50 = 2 diopter.