A pulse of light of duration `10^(-6)` s is absorbed completely by a small object initially at rest. If the power of the pulse is `60 xx 10^(-3)` W, calculate the final momentum of the object.

The initial rate of a first order reaction is 5.2xx10^(-6) "mol lit"^(-1)s^(-1) 298 K. When the initial concentration of reactant is 2.6xx10^(-3)"mol lit"^(-1) , calculate the first order rate constant of the reaction at the same temperature.

The speed of light in. water is 2.25 xx 10^(8) ms^(-1) . If the speed of light in vacuum is 3 xx 10^(8) ms^(-1) , calculate the refractive index of water.

A baby cries on seeing a dog and the cry is detected at a distance of 3.0 m such that the intensity of sound at this distance is 10^(-2) W m^(-2) . Calculate the intensity of the baby's cry at a distance 6.0 m

In a common emitter transistor amplifier , the output resistance is 500 k Omega and the current gain beta = 49 . If the power gain of the amplifier is 5 xx 10^(6) , the input resistance is

Monochromatic light of frequency 6 xx 10^(14) Hz is produced by a laser. The power emitted is 2.0 xx 10^(-3) W . How many photons per second on an average are emitted by the source ?