An object weighs 30N in air and 21N in water. The weight of the object when completely immersed in a liquid of relative density 1.4 is
Which of the following instruments is most suitable for measuring the outside diameter of a narrow pipe in a few millimeters in diameter?
Electrical power is transmitted at a high voltage rather than a low voltage because the amount of energy loss is due to
If the focal length of a camera is 20cm, the distance from the film at which the lens must be set to produce a sharp image of 100cm away is
The image of an object is located 6cm behind a convex mirror. If it's magnification is 0.6, calculate the focal length of the mirror