# Band Structure of an Open-Circuited p-n junction MCQ’s

This set of Electronic Devices & Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Band Structure of an Open-Circuited p-n junction”.

1. Which of the following equations represent the correct expression for the shift in the energy levels for the p-n junction?
a) Eo = Ecn – Ecp
b) Eo = Ecp – Ecn
c) Eo = Ecp + Ecn
d) Eo = -Ecp – Ecn

2. Calculate the Eo given that Nd=1.5*1010cm-3, Na=1.5*1010cm-3 at temperature 300K?
a) 1.5*1010eV
b) 0.256eV
c) 0eV
d) 4.14*10-21eV

3. The conduction band edge in the p material is not at the same level to that of conduction band edge in the n material. Is it true or false?
a) True
b) False

4. In a p-n junction, the valence band edge of the p material is greater than which of the following band?
a) Conduction band edge of n material
b) Valence band edge of n material
c) Conduction band edge of p material
d) Fermi level of p material

5. Calculate the value of Eo when pno=104cm-3 and ppo=1016cm-3 at T=300K.
a) 1meV
b) 0.7meV
c) 0.7eV
d) 0.1meV

6. What is the value of kT at room temperature?
a) 0.0256eV
b) 0.25eV
c) 25eV
d) 0.0025eV

7. Which of the following equations represent the correct expression for the band diagram of the p-n junction? (E1=difference between the fermi level of material and conduction band of n material and E2=difference between the conduction band of n material and fermi level of n material)
a) Ecn – E f = (1/2)*EG – E1
b) Ecn – E f = (1/2)*EG – E2
c) Ef – Ecp = (1/2)*EG – E1
d) Ecn – Ef = (1/2)*EG + E1

8. Calculate the value of Dp when µp=400cm/s and VT=25mV.
a) 1
b) 0.01
c) 0.1
d) 10

9. Is Vo depends only on the equilibrium concentrations. Is it true or false?
a) True
b) False

10. Calculate Vo when ppo=1016cm-3, pno=104cm-3 and Vt=25mV.
a) 69V
b) 6.9V
c) 0.69V
d) 0.069V