Question

an object is placed 15cm from a concave mirror of radius of curvature 90cm. calculate the position of image and magnification

Answer 1

hey , your answer is -
Given, u = - 15 cm. , R = -90cm
then , focal length f = - 90/2 = - 45

Now , by mirror formula -
1/v + 1/u = 1/f
=> 1/v = 1/f - 1/u
=> 1/v = - 1/45 + 1/15
=> 1/v = 2/45
=> v = 45/2

=> v = 22.5 cm
now, magnification
m = - v/u = - 22.5 / - 15
=> m = 1.5

hence, image is 22.5cm away from the mirror and it s negative sign show that image is virtual and erect .


★ hope u understand

Answer 2

Answer:

hey , your answer is -

Given, u = - 15 cm. , R = -90cm

then , focal length f = - 90/2 = - 45

Now , by mirror formula -

1/v + 1/u = 1/f

=> 1/v = 1/f - 1/u

=> 1/v = - 1/45 + 1/15

=> 1/v = 2/45

=> v = 45/2

=> v = 22.5 cm

now, magnification

m = - v/u = - 22.5 / - 15

=> m = 1.5

hence, image is 22.5cm away from the mirror and it s negative sign show that image is virtual and erect .

Explanation: