Electromagnetic Waves — Physics STD 12 Science — Question

The ionisation potential of hydrogen atom is 13.6 volt. The energy required to remove an electron in the n = 2 state of the hydrogen atom is(a) 27.2 eV(b) 13.6 eV(c) 6.8 eV                                          (d) 3.4 eV

The formula of kinetic mass of a photon is :

5 amperes of current is passed through a metallic conductor. The charge flowing in one minute in coulombs will be(a) 5 (b) 12(c) 1/12(d) 300

In Young's double slit experiment, 62 fringes are seen in visible region for sodium light of wavelength 5893 Å. If violet light of wavelength 4358 Å is used in place of sodium light, then number of fringes seen will be(a) 54(b) 64(c) 74       (d) 84

The emitter-base junction of a transistor is …… biased while the collector-base junction is ……. biased(a) Reverse, forward(b) Reverse, reverse(c) Forward, forward (d) Forward, reverse

Visible light passing through a circular hole forms a diffraction disc of radius 0.1mm on a screen. If an X-ray is passed through the same setup, the radius of the diffraction disc will be:

1. zero
2. < 0.1mm
3. 0.1mm
4. > 0.1m

Calculate the wavelength of electromagnetic waves of frequency 300MHz.

When a current in a circular loop is equivalently replaced by a magnetic dipole:

One metallic sphere A is given positive charge whereas another identical metallic sphere B of exactly same mass as of  A is given equal amount of negative charge. Then(a) Mass of  A and mass of  B still remain equal(b) Mass of  A increases(c) Mass of  B decreases(d) Mass of  B increases