Quantum physics

Which of the following observations of the photoelectric effect are failed to be explained by wave model? (select all)

• There is a minimum frequency of EM radiation required.

• The maximum energy of photoelectrons depends on frequency.

• The rate of emission of electrons depends on intensity.

• The effect is instantaneous.

A gamma-ray photon has energy 3 MeV. What is the frequency of this photon?

(h = 6.63×10⁻³⁴ J s, e = 1.6×10⁻¹⁹ C, c = 3.0×10⁸ m s⁻¹)

• 7.2 × 10²⁰ Hz

• 4.5 × 10³⁹ Hz

• 3.2 × 10⁻⁴⁶ Hz

• 1.4 × 10²¹ Hz

Which is the correct formula for the momentum of a photon?

• p=m/c

• p=E/c

• p=f/c

• p=mv

The minimum energy of electromagnetic radiation required to release an electron from a metal surface is called _______.

UV light of wavelength 2 × 10⁻⁷ m falls on surface of gold. Work function of gold is 4.9 eV. What is the maximum energy of emitted electrons?

(h = 6.63×10⁻³⁴ J s, e = 1.6×10⁻¹⁹ C, c = 3.0×10⁸ m s⁻¹)

• 1.3 eV

• 2.6 eV

• 3.9 eV

• 6.2 eV

Line spectrum produced by a hot gas is called the ________ line spectrum.

How many different photons can be absorbed by an atom if the atomic electrons have 6 energy levels?

• 6

• 12

• 15

• 20

What is the p.d. required to accelerate electrons from rest so that the electrons have a de Broglie wavelength of 4.0×10⁻¹⁰ m?

(e=1.6×10⁻¹⁹, m_e=9.11×10⁻³¹ kg, h=6.63×10⁻³⁴ J s.)

• 9.4 V

• 4.9 V

• 5.7 × 10²⁴ V

• 1.5 × 10⁻¹⁸ V

What is the term used to describe the fact that particles can behave as waves and waves can behave as particles?

• wave-particle disparity

• wave-particle tranquality

• wave-particle equality

• wave-particle duality