Question

An object is placed 10 cm in front of a concave mirror whose focal length is 15 cm. The object is 2.8 cm tall. Determine (a) the location of the image, taking a real image as a positive value and a virtual image as a negative value. (b) Determine the height of the image, where an upright image will have a positive height and an inverted image will have a negative height.

Answer 1

A)

As it is given that the mirror is concave then the focal length given with sign convention will be

And as given the object distance is

By mirror equation as we know that

Substituting the values we get,

​

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So the image is behind the mirror at a distance of 30 cm.

B)

As we know that magnification is given by

Substituting the values

So image height is