Two lenses in contact

1. The problem statement, all variables and given/known data

(a)Can a converging lens be made to diverging if it is placed into a liquid?

(b)What if?What about a converging mirror?





2. Relevant equations







2. Relevant equations



3. The attempt at a solution3. The attempt at a solution

(a)Let the focal length of the converging lens be f1,and the focal length of the lens be -f2.From the formula ,when the magnitude of f2 is larger than f1,the new focal length we get is smaller than 0,so converging lens can be made to be diverging.

Is it correct?

In (b),can we use the formula again?



THANKS!