How do you find the focal length using the displacement method?

How do you find the focal length using the displacement method?

Apply Lens formula,

1. 1f=1v−1u.
2. 1f=1D−u−1u.
3. ⇒1f=u−(D−u)(D−u)u.
4. ⇒1f=−D(D−u)u.

What is displacement method of lens?

If the distance between object and screen (D) is greater than 4f then there are two positions of the lens for which the image of object on the screen is distinct and clear. In these two positions the distance of object and image from lens are interchange.

How do you calculate focal length change?

How does the focal point change with a different index of refraction? Analytically, the focal length is described by the lens maker’s equation: 1/f = (n – 1)(1/R1 + 1/R2), where R1 and R2 are the radii of curvature, f is the focal length, and n is the index of refraction.

What is the formula for focal length of combination?

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. Focal Length of Concave Lens Experiment. The combined focal length for two thin lenses separated by a distance a (Figure 2) is given by the equation: 7.

How do you find the focal length given the magnification and object distance?

If you know the distance of the object you’re magnifying from the lens and the focal length of the lens, finding the distance of the image is easy with the lens equation. The lens equation is 1/f = 1/do + 1/di, where f = the focal length of the lens.

What is the formula of focal length of convex lens?

The focal length of convex lens formula is object distance multiplied by the image distance divided by the difference of the object distance and the image distance. Here, we will discuss how to find focal length of convex lens, perform the convex lens experiment class 12 to obtain the focal length of a convex lens.

What is magnification formula?

Magnification (m) = h / h’ Here, h is the height of the object and h’ is the height of the object. Besides, it can also be related to the object distance and image distance. So, it can be written as: m = -v / u.

What is magnification in lens?

Magnification of a lens is defined as the ratio of the height of an image to the height of an object. It is equal to the ratio of image distance to that of object distance.

What is the focal length of a convex lens of focal length 30cm?

Hence, the focal length of the combination of lenses is 60 cm.