JEE Main201912 Jan 2019Morning ShiftPhysicsRay OpticsActual
What is the position and nature of image formed by lens combination shown in figure? ( f 1 , f 2 are focal lengths)
Options
- A40 c m from point B at right; real
- B20 3 c m from point B at right, real
- C70 c m from point B at right; real
- D70 c m from point B at left; virtual
Correct answer
C. 70 c m from point B at right; real
Step-by-step solution
for convex lense, 1 V + 1 20 = 1 5 1 V = 1 5 - 1 20 = 4 - 1 20 V 1 = 20 3 cm for concave lense, Distance of first image from B = 20 3 - 2 = 14 3 c m 1 V - 3 14 = - 1 5 = 15 - 14 70 = 1 70 Real image 70   c m right of B .