Why the focal length of convex lens is always positive?
The direction of the incident parallel rays and refracted rays in case of convex lens is the same. So, the distance of the point where the incident rays ,after passing through convex lens ,converge which is called focal length of the lens, is positive. This means convex lens does converge parallel incident rays.Click to see…
The direction of the incident parallel rays and refracted rays in case of convex lens is the same. So, the distance of the point where the incident rays ,after passing through convex lens ,converge which is called focal length of the lens, is positive. This means convex lens does converge parallel incident rays.Click to see full answer. Consequently, is the focal length of a convex lens positive or negative?you can easily verify that the focal length is in the positive x direction for a convex lens while it is along the negative x direction for a concave lens. So f is positive for a convex lens and negative for a concave lens. The reason is the sign altering of v.Additionally, why the power of convex lens is positive? The power of a convex lens is positive as a convex lens has a positive focal length, while the power of a concave lens is negative as concave lens has a negative focal length. It is because focal length of convex lens is +ve and. Therefore power of convex lens is positive. why is the focal length of a convex mirror negative? f, the focal length, is positive for a concave mirror, and negative for a convex mirror. When the image distance is negative, the image is behind the mirror, so the image is virtual and upright. A negative m means that the image is inverted. Positive means an upright image.How is focal length calculated?To measure the focal length of a converging (convex) lens. Using the formula: 1/u + 1/v = 1/f, the focal length f of the lens can be found.
