Question

A convex lens of focal length 25 cm and a concave Lens of focal length 10 cm are placed in close contact with each other calculate the lens power of this combination

Answer 1

Powe=1/f where f is focal length in meter

P1=100/25=4 (convex lens)

P2=100/-10=-10(concave)

Now when we use formula P=P1+P2

We get P= 4+(-10)= -6

Answer 2

Hi Mate,

Given,

Focal Length (convex lens) = 25 cm

Focal Length (concave lens) = 10 cm

$P_1 = \frac{1}{f} = \frac{1}{25} cm = \frac{1}{25}×100 m = 4 D$

$P_2 = \frac{1}{f} = \frac{1}{10} cm = \frac{1}{100}×100 m = -10 D$

Now,

$P = P_1 + P_2$

$= 4 + (-10) D$

$= -6 D$

Hope This Helps You........(◕ᴗ◕✿)