Question

A glowing electric light bulb placed 15 cm from a concave spherical mirror produces a real image 8.9 from the mirror. the light bulb is moved to a position 20cm from the mirror

a) what is the image position? (answer with -1000 if the image does not exist)

Answer 1

The image will form at distance d = 7.75 cm from the mirror

Step-by-step explanation:

As we know that the bulb is placed at 15 cm distance from the concave mirror

Then the image will form at distance d = 8.9 cm

now we have

`(1)/(d_i) + (1)/(d_0) = (1)/(f)`

so we have

`(1)/(8.9) + (1)/(15) = (1)/(f)`

`f = 5.58 cm`

Now when bulb is placed at distance 20 cm from the mirror

then again we have

`(1)/(d_i) + (1)/(d_0) = (1)/(f)`

`(1)/(d_i) + (1)/(20) = (1)/(5.58)`

now we have

`d_i = 7.75 cm`