In an experiment, the resistance of a material is plotted as a function of temperature (in some range). As shown in the figure, it is a straight line. One may conclude that :

A transformer consisting of 300 turns in the primary and 150 turns in the secondary gives output power of 2.2 kW. If the current in the secondary coil is 10A, then the input voltage and current in the primary coil are :

In a photoelectric effect experiment the threshold wavelength of the light is 380 nm. If the wavelentgh of incident light is 260 nm, the maximum kinetic energy of emitted electrons will be:
Given E (in eV) = 1237/$$\lambda $$ (in nm)

The displacement of a damped harmonic oscillator is given by
x(t ) = e^–0.1t cos (10$$\pi $$t + f).
Here t is in seconds. The time taken for its amplitude of vibration to drop to half of its initial value is close to :