Question

A 2 cm tall object is placed 30cm in front of a concave mirror with focal length of 25 cm. What is the height of the image?

Answer 1

`- 10` cm

Step-by-step explanation:

`h_(o)` = height of the object = 2 cm

`h_(i)` = height of the image

`d_(o)` = distance of the object from the mirror = 30 cm

`f` = focal length of the mirror = 25 cm

`d_(i)` = image distance

using the mirror equation

`(1)/(d_(o)) + (1)/(d_(i)) = (1)/(f)`

`(1)/(30) + (1)/(d_(i)) = (1)/(25)`

`d_(i) = 150` cm

using the equation

`(h_(i))/(h_(o)) = (- d_(i))/(d_(o))`

`(h_(i))/(2) = (- 150)/(30)`

`h_(i) = - 10` cm