WorksheetsEngineering Physics-II Quiz
Total questions: 15
Worksheet time: 8mins
What is the main factor that determines the conductivity of a material?
Presence of free protons
Presence of free neutrons
Presence of free electrons
Presence of free positrons
Which of the following materials are examples of conducting materials?
Aluminum, Titanium, Lead
Plastic, Wood, Glass
Iron, Zinc, Nickel
Gold, Silver, Copper
What is the average velocity of free electrons with which they move towards the positive terminal under the influence of an electrical field?
Drift velocity
Collision time
Mean free path
Relaxation time
What is the definition of mobility in the context of conducting materials?
Average distance traveled by a free electron between two successive collisions
Rate of charge flow across unit area
Drift velocity of the charge carrier per unit applied electric field
Average time taken by a free electron between two successive collisions
What is the expression for electrical conductivity in a conductor?
σ = m / e
σ = 2mneτ
σ = E / J
σ = nev_d
What is the definition of thermal conductivity in a material?
Amount of heat flowing per unit time through the material per unit temperature gradient
Rate of charge flow across unit area
Average time taken by a free electron between two successive collisions
Average distance traveled by a free electron between two successive collisions
According to the Wiedemann – Franz law, what is the relationship between thermal conductivity and electrical conductivity of a metal?
They are inversely proportional
They are inversely proportional to the square of the absolute temperature
They are directly proportional
They are not related
What does the Fermi-Dirac distribution function represent?
Probability of an electron occupying a given energy level at absolute temperature
Average time taken by a free electron between two successive collisions
Rate of charge flow across unit area
Average distance traveled by a free electron between two successive collisions
At what temperature does the Fermi function vary as a step function for different energy values?
0K
100K
500K
1000K
What does the density of energy states represent?
Number of available electron states per unit volume in an Energy interval
Average distance traveled by a free electron between two successive collisions
Rate of charge flow across unit area
Average time taken by a free electron between two successive collisions
What is the expression for the density of charge carriers in the energy interval E and E + dE?
Z(E)dE = 2ndn / h
Z(E)dE = 2ndn
Z(E)dE = 2ndn / hma
Z(E)dE = 2ndn / hma^2
What is the main principle stated by Pauli's exclusion principle?
Electrons can occupy any state freely
Only one electron can occupy each state
Two electrons of opposite spins can occupy each state
Two electrons of the same spin can occupy each state
What is the average kinetic energy of an electron at point A in the metallic rod?
4kT
kT
2kT
3kT
What is the ratio of thermal conductivity to electrical conductivity of a metal according to the Wiedemann – Franz law?
Inversely proportional to the square of the absolute temperature
Inversely proportional to the absolute temperature
Directly proportional to the absolute temperature
Directly proportional to the square of the absolute temperature
What is the probability of occupation for E > EF at T = 0K?
0%
25%
50%
75%
