Question

two lenses of power +12D and -2D are placed in contact.What will be the focal length of combination

Answer 1

Explanation:

We know

P=P1+P2

hence power is 10D

F=1/P

hence F=0.1 m

Answer 2

The focal length of combination is, f=10 cm.

Definition of focal length:

The distance between the convex lens or a concave mirror and the focal point of a lens or mirror is called the focal length.

We know that, Power of combination, P = P1 + P2

Here according to question P1 = +12, P2 = –2D  

Focal length of the combination is given by,

$f=\frac{1}{p} \\\\\\ =\frac{1}{10} \mathrm{~m} \\\\ =\frac{1}{10} \times 100=10 \mathrm{~cm} \\ f=10 \mathrm{~cm}$

Hence, The combination's focal length is f=10 cm.

Learn more about focal length here,

https://brainly.in/question/2066166?msp_poc_exp=4

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