Class 12th

When light of maximum wavelength 300 nm falls on a photoelectric emitter, photoelectrons are liberated. For another emitter however light of maximum wavelength 600 nm causes photoelectric emission. The ratio of work functions of first emitter to second emitter will be

Rainbow is formed due to

A defective eye cannot see close objects clearly because their image is formed

The fringe width in Young's double slit experiment increases when

If two coherent waves are represented by y₁ = 4sinωt and y₂= 3sin(ωt+π/3)interfere at a point, the amplitude of resulting wave will be about

A plane electromagnetic wave EZ = 100 cos (6 * 10⁸ t + 4x) V/m, where x is in metre and t is in second. propagates in medium, what is refractive index of the medium?

A coil has resistance of 30 ohm and inductive reactance 20 ohm at 50 Hz frequency. If an ac source of 200 V, 100 Hz is connected across the coil, current in coil will be

According to Lenz's law of electromagnetic induction

The horizontal component of earth's magnetic field at a place is 4 * 10^–4 T and dip is 45°. A metal rod of length 20 cm is placed in north south direction and is moved at constant speed of 5 cm/s towards East. What is e.m.f. induced in the rod?

The resistance of a silicon junction diode, whose V - I characteristics is as shown in figure is (V_k = 0.7 V)