A convex lens of focal length 1.0m and a concave lens of focal length9.25m are 0.75m apart. A parallel beam of light is incident on the convex lens. The beam emerging after refraction from both lenses is

Options

A. parallell to the principal axis
B. convergent
C. divergent
D. none of the above

Answer

a.

Explanation

Power of system
`(1)/(f_(1))+(1)/(f_(2))-(d)/(f_(1)f_(2))=(1)/(1)+(1)/(-0.25)-(0.75)/((1)(-0.25))`
`=1-4+3=-3+3=0`
Since power of the system is zero, therefore the incident parallel beam of light will remain parallel after emerging from the system.