Question

A convex lens and a concave lens each having same focal length of 25 cm are put in contact to form a combination. The power in diopters of the combination is –

• A. zero
• B.
  • 4
• C. – 4
• D. 

Answer 1

P = P₁ + P₂

\ P = $\frac { 1 } { + 0.25 } + \frac { 1 } { - 0.25 }$

\ P = 0