BITSAT2011PhysicsRay OpticsActual
A thin convergent glass lens ( _ g =1.5 ) has a power of +5.0 D . When this lens is immersed in a liquid of refractive index , it acts as a divergent lens of focal length 100 ~cm . The value of must be
Options
- A4 / 3
- B5 / 3
- C5 / 4
- D6 / 5
Correct answer
B. 5 / 3
Step-by-step solution
P _ a P ₁ = ( _ g _ a -1 ) ( _ g ₁ -1 ) = +5 -100 / 100 =-5-5 ( _ g ₁ -1 )= _ g _ a -1 1.5 ₁ -1= -1 5 (1.5-1)=-0.1 array ll ₁= 1.5 0.9 = 5 3 array