JIPMER2016PhysicsRay Optics
A square wire of side 2.0 cm is placed 20 cm in front of a concave mirror of focal length 10 cm with its centre on the axis of the mirror and its plane normal to the axis. The area enclosed by the image of wire is
Options
- A7.5 ~cm ^2
- B6 ~cm ^2
- C2 ~cm ^2
- D4 ~cm ^2
Correct answer
D. 4 ~cm ^2
Step-by-step solution
Given, square wire of side =2 ~cm , u=-20 ~cm , f=-10 ~cm , Area of second wire = ? aligned & & 1 v + 1 u & = 1 f & & 1 v + 1 (-20) & = 1 -10 1 v =- 1 10 + 1 20 & & v & =-20 ~cm aligned We know that, m=- v u = -(-20) -20 =-1 Area of image Area of object =m^2 A_i A₀ =(-1)^2 A_i 2 2 =1 A_i=4 ~cm ^2