If two lenses of `+5` dioptres are mounted at some distance apart, the equivalent power will always be negative if the distance is

Draw two parallel lines at a distance 5cm apart.

Draw two parallel lines at a distance 5 cm apart.

Two lenses of power +12 D and -2 D are combined together. What is their equivalent focal length ?

In Ramsden eyepiece, the two planoconvex lenses each of focal length f are separated by a distance 12 cm. The equivalent focal length (in cm) of the eyepiece is

Two lenses of power + 12D and - 2D are combined together. What is their equivalent focal length?

Two lenses of power +12 D and -2D are combined together.What is their equivalent focal length?

Two convex lenses of focal length f_1 and f_2 are mounted coaxially separated by a distance. If the power of the combination is zero, the distance between the lenses is

Two convex lenses of focal length f_1 and f_2 are mounted coaxially separated by a distance. If the power of the combination is zero, the distance between the lenses is

Charge Q is divided into two parts which are then kept some distance apart . The force between them will be maximum if the two parts are

Charge Q is divided into two parts which are then kept some distance apart . The force between them will be maximum if the two parts are