Lenses and stuff..I need help!!! PLEASE?

Question

Assume object is 20 cm away from lens; image formed is 5cm away from the lens.

1. What is the focal length of this lense? (it's negative)

2. What is the magnification of this image?

3. If the object is 8 cm tall, how tall is the image?

4. What kind of image is formed in this diagram?

a. virtual and inverted

b. virtual and upright

c. real and inverted

d. real and upright

Answer 1

1.

if focal length is negative then it's a diverging lens, the image is always virtual

(1/20) + (1/-5) = (1/f)

f= - 6.7 cm

2.

M = -(-5/20) = 1/4

3.

8*(1/4) = 2cm

4.

b