Question

If the object is placed 6 cm from a concave mirror, the image distance is 12 cm. What is the focal length?

Answer 1

Answer:

72 cm

Explanation:

you have to multiply the both numbers with each other

Answer 2

Answer:

using mirror formula :- 1/v + 1/u = 1/f

1/12 +1/6 = 1/f

3/12 = 1/f

12/3 = f

4 cm = f

hence the focal length is 4cm

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