Question

statement of combination of two thin lenses​

Answer 1

The combination of two thin lens kept in contact .

When the two lenses are in contact then the focal length will be the sum of the reciprocal of the focal length of the lens .

When the two lenses are in contact then the resultant focal length can be calculated by using the statement .

Let the focal length of the lenses be f₁ and f₂ .

Let the focal length of the resultant combination be f .

$\dfrac{1}{f}=\dfrac{1}{f_1}+\dfrac{1}{f_2}$

The focal length of a convex lens is positive .

The focal length of a concave lens is negative .

Answer 2

Answer:

When the two lenses are in contact then the focal length will be the sum of the reciprocal of the focal length of the lens .

When the two lenses are in contact then the resultant focal length can be calculated by using the statement .

Let the focal length of the lenses be f₁ and f₂ .

Let the focal length of the resultant combination be f .

\dfrac{1}{f}=\dfrac{1}{f_1}+\dfrac{1}{f_2}

The focal length of a convex lens is positive .

The focal length of a concave lens is negative .