152k views
1 vote
An electron is trapped in a box of length L = 100 pm. There is a single node in the center of the box where the electron cannot exist. What is the energy of the electron, in eV?

User Ieugen
by
5.4k points

2 Answers

1 vote

Final answer:

To determine the energy of the electron in a quantum box with one node at the center, we calculate the electron's energy at the second energy level using the quantum particle in a box formula and convert the result to electron volts.

Step-by-step explanation:

The question is asking about the energy of an electron confined in a box with a single node in the center, which is a scenario that relates to the quantum particle in a box model in quantum mechanics, a topic in physics. To find the energy of the electron, we use the formula for the energy levels of a particle in a one-dimensional box:


En = \( \frac{n²h²}{8mL²} \)


where:

n is the principal quantum number,

h is the Planck's constant \( (6.626 \times 10⁽⁻³⁴⁾ J \cdot s) \),

m is the mass of the electron \( (9.109 \times 10⁽⁻³¹⁾ kg) \), and

L is the length of the box


Since there is a single node in the center of the box, the electron is in the second energy level (n=2), as nodes correspond to the n-1 rule. We convert the length of the box to meters (100 pm = 100 x 10-12 m) and plug these values into the formula to calculate the energy. To obtain the energy in electron volts (eV), we convert the result from joules by dividing by the charge of one electron \( (1.602 \times 10⁽⁻¹⁹⁾ C) \).


The energy of the electron in the box is then calculated and presented in eV.

User Vasantha Ganesh
by
6.3k points
0 votes

Answer is E= 24.092eV.

Step-by-step explanation: This numerical is based on the Particle in 1-D box.

For a particle in 1-D box the energy is calculated by


E_n=(n^2h^2)/(8mL^2)

where
E_n = allowed energies for a particle in a box

n = energy level

h = plank's constant

m = mass of a particle

L = length of a box

In this question, it is given the number of nodes from which we can calculate the value of "n"

Relationship between the number of nodes and the energy level is


l=n-1

l = number of angular nodes

Number of nodes given in the question is 1, so the energy level can be calculated from the above relation.


1=n-1\\n=2

Now, putting all the values in energy formula,


L=100*10^-^1^2m

Mass of electron =
9.11*10^-^3^1kg

n = 2

h =
6.63*10^-^3^4Js


E_2=((2)^2(6.63*10^-^3^4Js)^2)/(8(9.11*10^-^3^1kg)(100*10^-^1^2m)^2)\\E_2= (2)^2 (9.65*10^-^1^9J)

Converting Joules to eV


1J=6.242*10^1^8eV


E_2= (2)^2(6.023eV)\\E_2=24.092eV


User Matt Seymour
by
5.9k points