Electromagnetic Waves — Physics STD 12 Science — Question

As our eyes can not retrace the bent path of light, a stick, dipped in water, appears:

If a current of 3.0 amperes flowing in the primary coil is reduced to zero in 0.001 second, then the induced e.m.f. in the secondary coil is 15000 volts. The mutual inductance between the two coils is(a) 0.5 henry(b) 5 henry(c) 1.5 henry(d) 10 henry

Velocity of sound in air is 332m/s. Its velocity in vacuum will be:

1. > 332m/s
2. = 332 m/s
3. < 332m/s
4. Meaningless.

The cations and anions are arranged in alternate form in

In above question the energy of the characteristic X-rays given out is(a) Less than 40 keV(b) More than 40 keV(c) Equal to 40 keV(d) ≥  40 keV

X – rays and γ -  rays of the same energies may be distinguished by(a) Their velocity(b) Their ionising power(c) Their intensity(d) Method of production

In a transformer, the number of turns in primary and secondary are 500 and 2000 respectively. If current in primary is 48 A, the current in the secondary is

Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.

1. The power of a converging lens.
2. The focal length of a converging lens.
3. The power of a diverging lens.
4. The focal length of a diverging lens.

Huygen wave theory allows us to know(a) The wavelength of the wave(b) The velocity of the wave     (c) The amplitude of the wave(d) The propagation of wave fronts