Question

Power of a lens is 0.4D .what is its focal length

Answer 1

Focal length =1/power

F=1/0.4=2.5mts=250cm

Answer 2

The deviation caused by the light rays after refraction through it is called power.

We know that,

Power=1/focal length(in cm)

0.4D=1/f

--=->f=1/0.4=2.5cm

hope it helps u...................

pllzzzzzz....mark as brainliest