Ch5 L2 - Duality of light

The graph below shows the relation between the wavelength, 𝜆, associated with a massive moving object, and 1/v, where v is the velocity at which the object moves. Find the mass of the object

A photon of frequency 𝑓 and wavelength 𝜆 carries a momentum of 𝑝. What is the momentum of a photon of a frequency of 𝑓2?

• 2P

• P

• P/2

• P/4

A particle accelerator accelerates electrons through a potential difference Δ𝑉=550V. Find the wavelength of electrons as they exit the accelerator.

Initially, an electron has a velocity of v and a de Broglie wavelength 𝜆. If the electron’s velocity changes to v/4, then its de Broglie wavelength will be 

• 𝜆/2

• 4𝜆

• 2𝜆

• 𝜆/4

Which of the following correctly states the advantage of using electrons to produce images of very small objects compared to using electromagnetic waves?

• Electrons are reflected from objects more strongly than electromagnetic waves

• Electrons can penetrate deeper into objects than electromagnetic waves.

• A beam of electrons will in no way affect an object that it produces an image of, so it produces a more valid image than the ones that can be produced by electromagnetic waves.

• Electrons can easily be accelerated to velocities at which they have wavelengths much shorter than those of electromagnetic waves with wavelengths that are useful in forming images.

The ratio between the de Broglie wavelengths of two massive particles is 3∶2.If both particles have equal kinetic energies, what is the ratio between their masses?

• 4:9

• 3:2

• 9:4

• 2:3

• 4:1

• 1:16

• 1:4

• 16:1

If a radio station emits a wave with a frequency of 98.2 MHz, then the momentum of each emitted photon is ………..

What intensity of light would be needed to exert a 1 N force on a polished copper plate with an area of 2.5m²? Assume that all of the light incident on the copper plate is reflected.

• 30 MW/m²

• 60 MW/m²

• 24 MW/m²

• 12 MW/m²