If the work done in stretching a wire by 1 mm is 2 J, the work necessary for stretching another wire of same material but with double radius of cross-section and half the length by 1 mm is :-

A ultra violet light bulb, emitting 400 nm and infrared bulb emitting 700 nm wavelength radiation each are rated at 130 W. Then the ratio of the number of photons emitted per second by the UV & IR sources :-

Two vibrating tuning forks produce progressive waves given by y₁ = 4 sin(500πt) and y₂ = 2 sin(506πt). These tuning forks are held near the ear of a person. The person will hear α beats/s with intensity ratio between maxima and minima equal to β. Find the value of β-α. :-

An aluminium rod and a copper rod are taken such that their lengths are same and their resistances are also same. The specific resistance of copper is half that of aluminium, but its density is three times that of aluminium. The ratio of the mass of aluminium rod and that of copper rod will be :-

Two solid spherical planets of equal radii R having masses 4M and 9M their centre are separated by a distance 6R.What is the distance r of the point from the lighter planet where the gravitational force on the projectile is zero ?

A capacitor stores 60μC charge when connected across a battery. When the gap between the plates is filled with a dielectric, a charge of 120μC flows through the battery. The dielectric constant of the material inserted is :-

A spherical liquid drop of radius R is divided into eight equal droplets. If surface tension is T, then the work done in this process will be :-

N-mole of an ideal diatomic gas are in a cylinder at temperature T. Suppose on supplying heat to the gas, its temperature remains constant but n moles get dissociated into atoms. Heat supplied to the gas is :-

A Young's double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is:-