The focal length of the eyepiece
The focal length of the objective
Aperture of the eyepiece
Aperture of the objective
To measure the speed of an approaching car a police officer shines
To open a door easily, the handle should be fixed
To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor
To produce deflection in a television picture tube
To produce sound it is necessary that
Total internal reflection can not take place when light goes from :
Total internal reflection can take place when light travels from
Transformer is based upon the principle of
Transformers are used in
Transverse waves can propagate