Electrostatics — Physics STD 12 Science — Question

In hydrogen atom, when electron jumps from second to first orbit, then energy emitted is (a) – 13.6 eV(b) – 27.2 eV(c) – 6.8 eV(d) None of these

In a Young’s double slit experiment, the source illuminating the slits is changed from blue to violet. The width of the fringes (a) Increases(b) Decreases(c) Becomes unequal(d) Remains constant

According to Bohr’s theory of H atom, an electron can revolve around a proton indefinitely, if its path is:

If an element X has mass number and number of proton 8 then identify element X :

Photons of energy 6 eV are incident on a metal surface whose work function is 4 eV. The minimum kinetic energy of the emitted photo-electrons will be(a) 0 eV(b) 1 eV(c) 2 eV(d) 10 eV

 Identify the electromagnetic wave which is also known as heatwaves.

A charged particle is moved along a magnetic field line. The magnetic force on the particle is:

1. Along its velocity.
2. Opposite to its velocity.
3. Perpendicular to its velocity.
4. Zero.

The permeability of a paramagnetic substance is:

In the circuit of a triode valve, there is no change in the plate current, when the plate potential is increased from 200 volt to 220 volt and the grid potential is decreased from – 0.5 volt to –1.3 volt. The amplification factor of this valve is(a) 15(b) 20(c) 25 (d) 35

Who gave the Quantum model of hydrogen atom?