The ground state energy H-atom is 13.6 eV. The energy needed to ionize H –atom from its second excited state is
1.51 eV
3.4 eV
13.6 eV
12.1 eV
If λv, λx and λm represent the wavelengths of visible light, X-rays and microwaves respectively, then
λm > λx > λv
λv > λm > λx
λm > λv > λx
λv > λx > λm
The velocity of electromagnetic radiation in a medium of permittivity ε0 and permeability μ0 is given by
The charging current for a capacitor at any instant is 0.25 A.The displacement current across the capacitor plates at that instant is
The structure of solids is investigated by using
infrared radiations
In a plane electromagnetic wave, the electric field oscillates with a frequency of 2 × 1010 s-1 and an amplitude of 40 Vm-1. The wavelength of the wave is
3 × 10-3 m
2.5 × 10-2 m
1.5 × 10-2 m
4.5 × 10-3 m
The amplitudes of electric and magnetic fields in an electromagnetic wave are related to each other as
E0 = B0
E0 = cB0
E0 = B0 /c
E0 = c/B
A signal emitted by an antenna from a certain point can be received at another point of the surface in the form of
both (a) and (b)
A TV tower has a height of 100 m. How much population is covered by the TV broadcast if the average population density around the tower is 1000 km-2 (radius of earth = 6370 km)?
4 lakh
40,000
4000
40 lakh
In a certain region of space electric file and magnetic field are perpendicular to each other and an electron enters in region perpendicular to the direction of and both and moves undeflected, then velocity of electron is
