Advertisements
Advertisements
Question
The light emitted in the transition n = 3 to n = 2 in hydrogen is called Hα light. Find the maximum work function a metal can have so that Hα light can emit photoelectrons from it.
Advertisements
Solution
The Hα light can emit the photoelectrons if its energy is greater than or equal to the work function of the metal.
Energy possessed by Hα light (E) is given by
`E = 13.6 (1/n_1^2 - 1/n_2^2)eV`
`Here , n_1 = 2 , n_2 = 3`
`therefore E = 13.6 xx (1/4 - 1/4 )`
= `(13.6xx5)/36 = 1.89 eV`
= 1.90 eV
Hα light will be able to emit electron from the metal surface for the maximum work function of metal to be 1.90 eV.
APPEARS IN
RELATED QUESTIONS
State Bohr’s third postulate for hydrogen (H2) atom. Derive Bohr’s formula for the wave number. Obtain expressions for longest and shortest wavelength of spectral lines in ultraviolet region for hydrogen atom
Show that the circumference of the Bohr orbit for the hydrogen atom is an integral multiple of the de Broglie wavelength associated with the electron revolving around the orbit.
Write the expression for Bohr’s radius in hydrogen atom ?
The Bohr radius is given by `a_0 = (∈_0h^2)/{pime^2}`. Verify that the RHS has dimensions of length.
A positive ion having just one electron ejects it if a photon of wavelength 228 Å or less is absorbed by it. Identify the ion.
Radiation coming from transition n = 2 to n = 1 of hydrogen atoms falls on helium ions in n = 1 and n = 2 states. What are the possible transitions of helium ions as they absorbs energy from the radiation?
A beam of monochromatic light of wavelength λ ejects photoelectrons from a cesium surface (Φ = 1.9 eV). These photoelectrons are made to collide with hydrogen atoms in ground state. Find the maximum value of λ for which (a) hydrogen atoms may be ionized, (b) hydrogen atoms may get excited from the ground state to the first excited state and (c) the excited hydrogen atoms may emit visible light.
Answer the following question.
Calculate the orbital period of the electron in the first excited state of the hydrogen atom.
The energy associated with the first orbit of He+ is ____________ J.
If the radius of first electron orbit in hydrogen atom be r then the radius of the fourth orbit ill be ______.
Ratio of longest to shortest wavelength in Balmer series is ______.
The angular momentum of electron in nth orbit is given by
The simple Bohr model cannot be directly applied to calculate the energy levels of an atom with many electrons. This is because ______.
When an electron falls from a higher energy to a lower energy level, the difference in the energies appears in the form of electromagnetic radiation. Why cannot it be emitted as other forms of energy?
A hydrogen atom in is ground state absorbs 10.2 eV of energy. The angular momentum of electron of the hydrogen atom will increase by the value of ______.
(Given, Planck's constant = 6.6 × 10-34 Js)
In Bohr's theory of hydrogen atom, the electron jumps from higher orbit n to lower orbit p. The wavelength will be minimum for the transition ______.
The radius of the nth orbit in the Bohr model of hydrogen is proportional to ______.
Using Bohr’s Theory of hydrogen atom, obtain an expression for the velocity of an electron in the nth orbit of an atom.
On the basis of Bohr's theory, derive an expression for the radius of the nth orbit of an electron of hydrogen atom.
State the Bohr's postulate of angular momentum of an electron.
