Ray Optics Test...

A lens of power + 2 dioptres is placed in contact with a lens of power –1 diopotre. The combination willbehave like

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 and type of the lens should be

We combined a convex lens of focal length f₁ and concave lens of focal lengths f₂ and their combined focal length was F. The combination of these lenses willbehave like a concave lens, if

A convex lens has a focal length f. It is cut into two parts along the dotted line as shown in the figure. Thefocal length of each part will be

An object has image thrice of its original size when kept at 8 cm and 16 cm from a convex lens. Focal length of the lens is

The combination of a convex lens (f = 18 cm) and athin concave lens (f = 9 cm) is

The plane faces of two identical piano-convex lenses each having focal length of 40 cm are pressed against each other to form a usual convex lens. The distance from this lens, at which an object must be placed to obtain a real, inverted image with magnification one is

The unit of focal power of a lens is

A convex lens is in contact with concave lens. The magnitude of the ratio of their focal length is 2/3. Their equivalent focal length is 30 cm. What are theirindividual focal lengths

If two + 5 D lenses are mounted at some distance apart, the equivalent power will always be negative ifthe distance is