- #1

hidemi

- 208

- 36

- Homework Statement
- The two lenses shown are illuminated by a beam of parallel light from the left. Lens B is then moved slowly toward lens A. The beam emerging from lens B is:

A. initially parallel and then diverging

B. always diverging

C. initially converging and finally parallel

D. always parallel E. initially converging and finally diverging

The answer is A

- Relevant Equations
- 1/f = 1/f1 + 1/f2 - x/f1*f2

I know what happens initially, calculated as follows.

1/∞ ＋ 1/q = 1/50, q=50

1/-25 + 1/q = 1/-25, q= ∞

However, how do we know about the after when the two lenses get closer to each other?

1/∞ ＋ 1/q = 1/50, q=50

1/-25 + 1/q = 1/-25, q= ∞

However, how do we know about the after when the two lenses get closer to each other?