Two convex lenses separated by a distance are brought in contact. The focal length of the combination

Question

Two convex lenses separated by a distance are brought in contact. The focal length of the combination (A) Decreases (B) Increases (C) Decreases only when d is smaller than the focal length (D) Increases only when d is smaller than the focal lenght

Tardigrade Admin · Accepted Answer

P = P1 + P2 - x P1 P2. When put in contact x -0 . When P increases and focal length decreases

Q. Two convex lenses separated by a distance are brought in contact. The focal length of the combination

Decreases

Increases

Decreases only when d is smaller than the focal length

Increases only when d is smaller than the focal lenght

$P = P_{1} + P_{2} - x P_{1} P_{2}$ . When put in contact x -0
. When P increases and focal length decreases

Q. Two convex lenses separated by a distance are brought in contact. The focal length of the combination

Decreases

Increases

Decreases only when d is smaller than the focal length

Increases only when d is smaller than the focal lenght

P=P1​+P2​−xP1​P2​. When put in contact x -0 . When P increases and focal length decreases

$P = P_{1} + P_{2} - x P_{1} P_{2}$ . When put in contact x -0
. When P increases and focal length decreases