As per Aufbau’s principle, orbital or subshell with lowest energy should be filled first. The ascending order of orbital’s energy is given by 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 4f, 5d, 6p, 7s. So 2s orbital should be filled first.

Louis de Brogie gave realation between momentum and wavelength as λ = h/p. Here h is Planck’s constant, whose value is 6.626 x 10^-34 J/s. Wavelength = h/mv = 2 x 10^-34 m (momentum p = mass m x velocity v).

As per spectral lines of hydrogen, when an electron jumps from n_th orbit to 2^nd orbit, it’s in Balmer series (provided that n = 3, 4, 5….). For Balmer series, electron emits waves in visible region.

The suitable conditions of cathode ray discharge tube are low pressure and high pressures. Pressure can be adjusted by evacuated tubes. High voltage is applied across electrodes and current starts flowing through tube.

Zinc sulfide is a phosphorescent material, which has been coated on anode. when cathode rays strike on anode, electrons hit on Zinc sulfide screen, hence creating a bright spot.

An atom is written in symbol ZXA. By comparing it to ₁₇Cl³⁷, we get a number of protons as 17 and mass number as 37. Mass number – proton number = neutron number. Number of neutrons is 37 – 17 = 20. No. of protons = No. of electrons = 17.

As we know, Heisenberg’s principle of uncertainty states that Δx. Δp ≥ h/4π, x is position, p is momentum and “h” is Planck’s constant. Δx = Δp; Δx. Δx = h/4π; Δx = ?h/4π

Heisenberg’s principle of uncertainty states that product of relative momentum and velocities is equal to greater than h/4π, where is “h” is Planck’s constant and is equal to 6.626 x 10^-34 Js. Hence above statement is true.

Louis de Brogie gave realation between momentum and wavelength as λ = h/p. Here h is Planck’s constant, whose value is 6.626 x 10^-34 J/s. Wavelength = h/mc = 6.626 x 10^-34 Js/(3.313 x 10^-34 kg x 3 x 10⁸ m/s) = 0.67A°.

Yes, it’s a limitation of Bohr’s model that it could not splitting of spectral lines in magnetic field that is Zeeman effect and also in electric field also known as a stark effect. so above statement is true.