Questions from Modern Physics

Q: Suppose that positron–electron annihilations occur on the line 3 cm

Suppose that positron–electron annihilations occur on the line 3 cm from the center of the line connecting two detectors. Will the resultant photons be counted as having arrived at these detectors sim...

Q: According to this model, which statement is true about the energy

According to this model, which statement is true about the energy-level spacing of dots of different sizes? a. Smaller dots have equally spaced levels, but larger dots have energy levels that get far...

Q: Why do the transition elements (Z = 21 to 30)

Why do the transition elements (Z = 21 to 30) all have similar chemical properties?

Q: When a given dot with side length L makes a transition from

When a given dot with side length L makes a transition from its first excited state to its ground state, the dot emits green (550 nm) light. If a dot with side length 1.1L is used instead, what wavele...

Q: Dots that are the same size but made from different materials are

Dots that are the same size but made from different materials are compared. In the same transition, a dot of material 1 emits a photon of longer wavelength than the dot of material 2 does. Based on th...

Q: One advantage of the quantum dot is that, compared to many

One advantage of the quantum dot is that, compared to many other fluorescent materials, excited states have relatively long lifetimes (10 ns). What does this mean for the spread in the energy of the p...

Q: Take the size of a Rydberg atom to be the diameter of

Take the size of a Rydberg atom to be the diameter of the orbit of the excited electron. If the researchers want to perform this experiment with the rubidium atoms in a gas, with atoms separated by a...

Q: Assume that the researchers place an atom in a state with n

Assume that the researchers place an atom in a state with n = 100, l = 2. What is the magnitude of the orbital angular momentum L associated with this state? a. 2 ħ; b. 6 ħ; c. 200 ħ; d. 10...

Q: How many different possible electron states are there in the n =

How many different possible electron states are there in the n = 100, l = 2 subshell? a. 2; b. 100; c. 10,000; d. 10.

Q: In the Bohr model, what is the principal quantum number n

In the Bohr model, what is the principal quantum number n at which the excited electron is at a radius of 1 µm? a. 140; b. 400; c. 20; d. 81.