## Question

### Solution

Correct option is

12.75 eV

Energy of H-atom in the ground state

= –13.6 eV.

Ionization energy of the hydrogen in excited state equal to +0.85 eV means

Energy of H-atom in the excited state = –0.85 eV

∴ Energy emitted = –0.85 – (–13.6 eV)

= 12.75 eV.

#### SIMILAR QUESTIONS

Q1

Calculate the energy of a mole of photons of radiations whose frequency is ?

Q2

A 100 watt butt bulb emits monochromatic length of wavelength 400 nm. Calculate the number of photons emitted per second by the bulb.

Q3

Calculate the kinetic energy of the electron eject when yellow light of frequency 5.2 × 1014 sec–1 falls on the surface of potassium metal. Threshold frequency of potassium is 5 × 1014 sec–1.

Q4

The threshold frequency v0 for a metal is 7.0 × 1014 s–1. Calculate the kinetic energy of an electron emitted when radiation of frequency v = 1.0 × 1015 s–1 hits this metal.

Q5

Calculate the wavelength of the spectral line obtained in the spectrum of Li2+ ion when the transition takes place between two levels whose sum is 4 and the difference is 2.

Q6

Calculate the wavelength of the radiation emitted when an electron in a hydrogen atom undergoes a transition from 4th energy level to the 2nd energy level. In which part of the electromagnetic spectrum does this line lie?

Q7

Calculate the velocity of electron in the first Bohr orbit of hydrogen atom. Given that

Planck’s constant, h = 6.626 × 10–34 Js,

mass of electron = 9.11 × 10–31 kg and

1 J = 1 kg m2s–2.

Q8

Calculate ionization energy of the hydrogen atom.

Q9

The ionisation energy of He+ is . Calculate the energy of first stationary state of Li2+.

Q10

Calculate the wavelength associated with an electron

(mass 9.1 × 10–31 kg) moving with a velocity of 103 m sec–1

(h = 6.6 × 10–34 kg m2 sec–1)