you are given three lenses.1)a concave lens of focal length 25 cm 2)a convex lens of focal length 1/4m 3)a convex lens of focal length 100cm
​which combination out of these three lenses will form  a lens of zero power

Dear Student ,
If we take the concave lens of focal length 25 cm and convex lens of focal length 1/4 m = 25 cm then their combination is zero .
Here the combination of this two lenses has the power of ,
P = 1/f + 1/f = (-1/25) +(1/25) = 0 

Hope this helps you .
Regards

  • 5
no idea of 10th becoz i m still in 9th
  • -3
1 and 2
  • -1
Concave lens of focal lenght 25 com and convex lens of focal lenght 1/4 m i.e. 25 cm.
  • 2
Because their combination will be like -25+25=0
  • 1
What are you looking for?