Question

1. Atoms can only emit certain wavelengths of light because

a) not every color actually exists in nature.

b) light is made of discrete particles called photons.

c) their electrons are limited to discrete energies.

d) All atoms can emit continuous spectra.

2. How many red photons, with wavelength of 650 nm, does it take to equal the energy of a single 6.5 nm x-ray photon?

3. In a photoelectric effect experiment, light with frequency below the sample's cut-off frequency is used. What effect does increasing the brightness of the light have?

a) The current increases.

b) The current decreases.

c) The current can either increase or decrease, depending on the material in the sample.

d) No effect because no current is produced.

4. Why don't we observe matter-waves in the macroscopic world?

a) Because the wavelengths of macroscopic objects are much smaller than their size.

b) Because the wavelengths for macroscopic objects are much larger than their size.

c) Because only subatomic particles show wave/particle duality.

d) We do observe them; ocean waves are an example.

5. Why can electrons in an atom orbit the nucleus only from certain special radii?

a) Because they interfere destructively with each other.

b) Because they behave like waves which must be continuous all around the orbit.

c) Because they behave like spheres of small but finite size.

d) Because of electrostatic attraction to the nucleus.

Answer 1