How do you find the combined focal length of two lenses?

How do you find the combined focal length of two lenses?

Combined focal length (F): =f 1 f 2 /[f 1 + f 2] F = 10x(-20)/[10-20] = +20 cm The focal length of the combination is positive and so it acts as a convex lens.

When the two thin lenses are put in contact the focal length of the combination is?

When two thin lenses are kept in contanct, the focal length of the combination is. the geometricamean of the two focal lenghts.

What is the power of the combination of lenses if two thin lenses of focal length f1 and f2 are in contact *?

The combination is equivalent to a single lens of power.

What is the focal length of a thin lens?

The focal length of a thin lens is related to the radii of curvature of its two surfaces. 1/f = (n2 – n1)(1/R1 – 1/R2). Ri is positive, if xo and the center curvature are on the opposite sides of the respective surface. Ri is negative, if xo and the center curvature are on the same side of the respective surface.

What is combination of thin lens?

Combination of thin lenses in contact An object is placed at O on the common principal axis. The lens A produces an image at I1 and this image acts as the object for the second lens B. PI1=v1, image distance for the first lens (A) and also object distance for second lens (B).

What is combination lens?

Combination of lenses. When two lenses are used in combination, the first one forms an image that then serves as the object for the second lens. The magnification of the combination is the ratio of the height of the final image to the height of the object. This is the final image produced by the combination of lenses.

What happens when two lenses are combined?

Combination of lenses. When two lenses are used in combination, the first one forms an image that then serves as the object for the second lens. The magnification of the combination is the ratio of the height of the final image to the height of the object.

When two thin lenses are kept in contact prove that their combined or effective focal length f is given by?

When Two Thin Lenses Are Kept in Contact, Prove that Their Combined Or Effective Focal Length F is Given by : 1/F = 1/F_1 + 1/F_2 Where the Terms Have Their Usual Meaning.

What is the power of combination of convex lens and concave lens of the same focal length?

Hint: When a concave lens and a convex lens of the same focal length are in contact, then the power of the lens combination will be zero and its focal length will be infinite. Therefore, the combination behaves as a plane glass plate.

What is coaxial lens?

Coaxial lenses are lenses having common principal axes. A compound microscope, in its simple form, consists of coaxial lens (two lenses having common principal axes) mounted on the outer ends of two hollow metallic tubes. One of the two lenses acts as the objective and the other as the eyepiece.

What is the focal length of the combination?

The focal length of the combination of two convex lenses in contact is f. and if they are separated by a distance, then focal length of the combination is f1. .

What is lense combination?

How do you find the common focal length of two lenses?

The common focal length for a system, where two thin lenses are sharing an axis are kept in contact with each other, is given by the following formula. \\(\\frac{1}{f} = \\frac{1}{f1} + \\frac{1}{f2}\\) where, f is the combined focal length. f 1 is the focal length of the first lens. f 2 is the focal length of the second lens.

What is equivalent focal length?

Its focal length is known as equivalent focal length. For the above lens If f 1 >f 2 the combined lens behaves as a concave lens. If f 2 > f 1 the combined lens behaved as a convex lens.

When the distance of separation between the two lenses is infinite?

When the distance of separation between the two lenses (d) if equal to the sum of the individual focal lengths (f1 + f2), the combined focal length is infinite. This makes the refracted light rays parallel to each other.

What is the condition for a lens to behave like a convex?

Note : above two conditions are valid if one lens is convex and the other is concave lens . If both lenses are convex then the combined lens will behave like a convex lens.