If a convex lens of focal length 80 cm and a concave lens of focal length 50 cm are combined together , what will be their resulting power ?

Radius of one arm of hydraulic lift is four times of radius of other arm . What force should be applied on narrow arm to lift 100 kg

Zener diode is used for

If K.E of a free electron is doubled its de- Broglie wavelength changes by the factor

The nature of frictional force is

The time taken by a alternating current 50 hz in reaching from zero to maximum value will be

Torque acting on an electric dipole in a uniform electric field is maximum if the angle  between p and E  is

To get three images of a single object, one should have two plane mirrors at an angel of

Which of the following radiations has the least wavelength ?

The mass of a man standing on a lift is 60kg What is the weight when he is standing on lift which is moving upward with acceleration 4.9 m second per square ?