Please read the questions with no points (zero-point question), and then answer the following multiple-choice questions. Questions are from modules 1, 2, 3.1 and 3.2

1. A black bodys surface temperature is 7000 ⁰C. Now answer the following questions: 1.a. What would be the power density (W/m^2) on its surface? (Points 5) Ans. (i) 1.6*10^8 (ii) 2.6*10^8 (iii) 3.6*10^8 (iv) 4.6*10^8 (v) 5.6*10^8 1.b. What would be the peak wavelength (micrometer) of its radiation? (Points 5) Ans. (i) 0.4 (ii) 0.5 (iii) 0.6 (iv) 0.7 (v) 0.8 1.c. What would be the energy (eV) of this wavelength? (Points 5) Ans. (i) 1 (ii) 3 (iii) 5 (iv) 7 (v) 9 1.d. What would be the approximate photon color? (Points 5) Ans. (i) Green (ii) Yellow (iii) Red (iv) Black (v) Violet

2. At 427 ⁰C, what would be the bandgap (eV) of GaAs ? (Point 5) Ans. (i) 0.23 (ii) 0.67 (iii) 1.23 (iv) 1.75 (v) 2.15

3. GaN has conduction band energy level -4.1 eV away from vacuum level and has bandgap of 3.43 eV. Now answer the following questions: 3.a. What would be the position of the intrinsic fermi level (eV)? (Point 5) Ans. (i) -5.82 (ii) -4.1 (ii) -3.43 (iv) 7.53 (v) 0.67 3.b. What would be the position of energy level (eV) valence band? (Point 5) Ans. (i) -5.82 (ii) -4.1 (ii) -3.43 (iv) -7.53 (v) -0.67

1.a. What would be the power density (W/m^2) on its surface?

a) 1.6*10^8

b) 2.6*10^8

c) 3.6*10^8

d) 4.6*10^8

e) 5.6*10^8

1.b. What would be the peak wavelength (micrometer) of its radiation?

a) 0.4

b) 0.5

c) 0.6

d) 0.7

e) 0.8

1.c. What would be the energy (eV) of this wavelength?

a) 1

b) 3

c) 5

d) 7

e) 9

1.d. What would be the approximate photon color?

a) Green

b) Yellow

c) Red

d) Black

e) Violet