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19. A concave mirror is used to focus the image
of a flower on a nearby well 120 cm from the
flower. If a lateral magnification of 16 IS
desired, the distance of the flower from the
mirror should be
[MP PET 1986]
(a) 8cm
(b) 12cm
(C) 80cm
(d) 120 cm
Answers
Answer:
8cm.
Explanation:
Since, the magnification of the concave mirror is given as 16. So, if we take the image distance as v and the object distance as u. So, we get that the v/u will be 16. Again, from the question we get that the v=u+120. The concave mirror is placed at a distance of 120cm.
So, on substituting the value of the v in the magnification equation we will get that (120+u)/u=16. Hence, we will get that 120+u=16u or 15u=120. So, on solving we will get the u as 8cm.
Answer:
Hence option A is correct
Explanation:
The simple formula for magnification is as;
M = I / O;
= - v/ u
Where v is the distance from image, u is the distance from the object.
Distance between flower and image is 120cm
Appying the formula;
16 = - (120-u)/u ;
16u = -120 + u
15u = -120
U = - 8 cm
Hence option A is correct