A concave mirror gives an image three times as large as the
object placed at distance of a20 cm from it. For the image to
real, the focal length should be
a) 10 cm (b) 15 cm ()20 cm
(d) 30 cm
Answers
Answered by
0
Answer:
Answer is : 15 centimetres
Answered by
2
Answer:
By convention u=-20
Since magnification is 3 =v/u and u=-20, v=-60
By using the formula 1/v +1/u= 1/f
-1/20+ (-1/60)=1/f
-4/60=1/f
f=-15
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