If a beam of electrons impinges on an energy barrier of height 0.030eV...
Given E = 0.040 eV = 0.040 x 1 .6 x1 0
-19J = 0.064 ,10
-19J
V
0 = 0.030 eV = 0.030 x 1.6 x 10
-19 J
E>V
0Then the fraction of electrons reflected, the reflectance is given by
We know
P
1 = 1.07x 10
-25 kg. m/sec
Reflectance
Reflectance = 0.1
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If a beam of electrons impinges on an energy barrier of height 0.030eV...
Problem:
A beam of electrons with an energy of 0.040 eV impinges on an energy barrier of height 0.030 eV and infinite width. Find the fraction of electrons reflected at the barrier.
Solution:
To determine the fraction of electrons reflected at the barrier, we need to consider the energy of the impinging electrons and the height of the energy barrier.
Step 1: Calculate the transmission coefficient:
The transmission coefficient (T) represents the probability that an electron will pass through the barrier. It can be calculated using the formula:
T = 1 / (1 + (V0^2 / E^2) * sin^2(2kL))
where V0 is the potential height of the barrier, E is the energy of the electrons, k is the wave vector, and L is the width of the barrier.
In this case, the barrier has infinite width, so L is not relevant. Therefore, the formula simplifies to:
T = 1 / (1 + (V0^2 / E^2))
Substituting the given values, we have:
T = 1 / (1 + (0.030 eV / 0.040 eV)^2)
T = 1 / (1 + (0.75)^2)
T = 1 / (1 + 0.5625)
T = 1 / 1.5625
T ≈ 0.64
Step 2: Calculate the reflection coefficient:
The reflection coefficient (R) represents the probability that an electron will be reflected at the barrier. It can be calculated using the formula:
R = 1 - T
Substituting the value of T calculated in step 1, we have:
R = 1 - 0.64
R ≈ 0.36
Step 3: Calculate the fraction of reflected electrons:
The fraction of reflected electrons (F) is calculated by dividing the number of reflected electrons by the total number of electrons. Since R represents the probability of reflection, F can be represented as:
F = R / (T + R)
Substituting the values of R and T calculated in steps 1 and 2, we have:
F = 0.36 / (0.64 + 0.36)
F = 0.36 / 1
F = 0.36
Therefore, the fraction of electrons reflected at the barrier is 0.36, or 36%.
If a beam of electrons impinges on an energy barrier of height 0.030eV...
If a bean of electron impings on an energy barrier of high 0.030 electron volt and of infinite with find of fraction of electron reflected and transmitted at the barrier if the energy of impings electron 0.040electron volt and 0.025electron volt