we combine a convex lens of focal length f1 and concave lens of focal length f2 and their combined focal length was F. the combination of these lenses will behave like a aconcave lens if:

  • f1>f2
  • f1<f2
  • f 1 =f2
  • f1 less than or equal to f2
  • none of these


The lens in this case would be a Compound Lens which neither behaves like a Convex or a Concave Lens. It is normally used a corrector for rectifying lens aberration etc.

  • -2

 acc to me  for convex lens f1 is positive and for concave f2 is negative.......for combination to behave like convex if f2>f1

so 2nd option is correct i think

  • 4

so is tha answer none of these....???

  • 4
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