Question

1.The minimum wavelength and the minimum wave length for visible light is about 0.4 um and 0.7 um, respectively . Assume that the velocity of light is a constant of 3.0x10^8 m/s and Planck's constant is 4.13x10^-15 eV-s. What kind of material will appear colored?

(a)The material with band gap of 1.0eV

(b)The material with band gap of 2.0eV

(c)The material with band gap of 3.2eV

(d)The material with band gap of 3.5eV

2.Which kind of material is most likely a hard magnetic material?

(a) pure copper (b) single crystal iron

(c) very fine single domain iron-cobalt particle within a non magnetic matrix phase

(d) iron ingot with large grain size

3.What kind of optical fiber can has largest intensity of output impulse?

(a) Step-index optical fiber with high index material in core

(b) Graded-index optical fiber with high index material in core

(c) Step-index optical fiber with low index material in core

(d) Graded-index optical fiber with low index material in core

4.The room-temperature electrical conductivity if intrinsic silicon is 4*10^-4 (ohm-m)^-1.An extrinsic p-type silicon material is desired having a room-temperature conductivity of 150 (ohm-m)^-1 .Specify an impurity type as well as its concentration in atom percent to yield these electrical characteristics?

(a) 1.34*10^-5 at% of Phosphorus

(b) 6.7*10^21 at% of Arsenic

(c) 1.34*10^-5 at% of Boron

(d) 6.7*10^21 at% of Aluminum

5.what structure is for a stainless steel 430 with 25 % Cr and 0.20 % C ?

6.which structure is for a stainless steel 304 with 19% Cr and 10% Ni?

7.Which metal Is not suitable for cold working?

(a) Aluminum (b) nickel (c) magnesium (d) copper

8.What is the carbon content of a h ypoeutectic plain carbon steel containing 9.1 % eutectoid ferrite ?

9.Conductive polymers require

(a) large amount of lone pairs

(b) high molecular polarity

(c) long conjugation length

(d) short carbon-to-carbon distance

10.Which is the crystal structure of a silicon wafer for IC

(a) single crystal

(b) poly-crystal with columnar structure

(c) poly-crystal with equiaxed grairn

(d) poly-crystal with hybrid structure

Answer 1