Question

Does someone know how to do math with that equation

Answer 1

f = 5 cm

Step-by-step explanation:

using the thin lens equation, given as follows:

`(1)/(f) = (1)/(d_(o))+(1)/(d_(i))\\`

where,

f = focal length = ?

do = the distance of object from lens = 20 cm

di = the distance of image from lens = 6.6667 cm

Therefore,

`(1)/(f) = (1)/(20\ cm)+(1)/(6.6667\ cm)\\\\(1)/(f) = 0.199999\ cm^(-1)\\\\f = (1)/(0.199999\ cm^(-1))\\\\`

f = 5 cm