A candle placed 25 cm from a lens, forms an image on a screen placed 75 cm on the other end of the lens. The focal length is + 18.75 cm and is a convex lens.
The correct option is A True
In concave lens, image is always formed on the same side of the object.
Hence the given lens is a convex lens for which u = – 25 cm, v = 75 cm.
By using 1f=1v−1u⇒1f=1(+75)−1(−25)⇒f=18.75 cm