Login

Experts please answer this quwstion. Tomorrow is my exam.

Experts please answer this quwstion. Tomorrow is my exam. 10. A concave mirror forms a real image of an object placed in front of it at a distance 30 cm. of size three times the size of object. Find (a) the focal length of mirror (b) position of image. Ans. (a) 22•5 cm, (b) 90 cm in front of mirrcr.

Dear student,
Given,
Object distance, u=-30cm
Magnification=-3
​​​​​​m=-v/u
-3=-v/(-30)
v=-90cm
Using the mirror formula,
1v+1u=1f1(-90)+1(-30)=1f-190-130=1f1f=-30-902700f=22.5 cm

So, (a)the focal length of mirror is 22.5cm.
(b)the position of image is 90 cm and negative sign indicates the real image in front of mirror.
Regards

  • 1
View Full Answer
What are you looking for?