Question

a convex mirror has a focal length of 15 cm. calculate the position of the image when an object is placed at 20cm from the mirror what is the magnification draw a ray diagram with a proper scale

Answer 1

Answer:

In the present problem, the object is placed at a position which is between f and 2f so the image will be formed between infinity and 2f.

logic is had the object been at f …the image will be at infinity and if it is at 2f the image will come to 2f

using the mirror relation

1/v + 1/u = 1/f where u, v, f are object distance, image distance, and focal length respectively.

u= 20 cm f=15 cm (the sign convention is a coordinate convention with the mirror at origin and object on the positive x-axis)

so 1/v = 1/f - 1/u , = 1/15 - 1/20

= 5/(15x20)= 1/60 therefore v= 60 cm

so the image will be formed at 60 cm

with magnification m= v/u = 60/20 = 3

the image will be 3 times larger and real

• Ray Diagram

Answer 2

Explanation:

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