Question

two lens have power of a) +2 b) -4D what is the nature of focal length of each lens​

Answer 1

Answer:

what is going on here I don't know sorry my dear I am not sure if you are aware from me

Answer 2

power of a lens is the reciprocal of its focal length

power = 1/ focal length

therefore focal length = 1/ power

focal length of. lens a = 1/2 = 0.5 m

focal length of b = 1/-4 = - 0.25m