The charge on a hole is equal to the charge of

(1) Zero               

(2) Proton

(3) Neutron         

(4) Electron

Subtopic:  Types of Semiconductors |
 62%
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A \(Ge\) specimen is doped with \(Al\). The concentration of acceptor atoms is \(\sim10^{21}~\text{atoms/m}^3\). Given that the intrinsic concentration of electron hole pairs is \(\sim10^{19}/\text{m}^3\) the concentration of electrons in the specimen is:
1. \(10^{17} / \text{m}^3 \) 2. \(10^{15} / \text{m}^3 \)
3. \(10^4 / \text{m}^3 \) 4. \(10^2 / \text{m}^3\)
Subtopic:  Types of Semiconductors |
 70%
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Which of the following has negative temperature coefficient of resistance 
(1) Copper               

(2) Aluminium

(3) Iron                   

(4) Germanium

Subtopic:  Types of Semiconductors |
 85%
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In semiconductors at a room temperature 

(1) The valence band is partially empty and the conduction band is partially filled

(2) The valence band is completely filled and the conduction band is partially filled

(3) The valence band is completely filled

(4) The conduction band is completely empty

Subtopic:  Energy Band theory |
 70%
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Regarding a semiconductor which one of the following is wrong 

(1) There are no free electrons at room temperature

(2) There are no free electrons at 0 K

(3) The number of free electrons increases with rise of temperature

(4) The charge carriers are electrons and holes

Subtopic:  Types of Semiconductors |
 74%
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Which of the following statements is true for an N-type semi-conductor 

(1) The donor level lies closely below the bottom of the conduction band

(2) The donor level lies closely above the top of the valence band

(3) The donor level lies at the halfway mark of the forbidden energy gap

(4) None of above

Subtopic:  Types of Semiconductors |
 70%
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Choose the correct statement

(1) When we heat a semiconductor its resistance increases

(2) When we heat a semiconductor its resistance decreases

(3) When we cool a semiconductor to 0 K then it becomes super conductor

(4) Resistance of a semiconductor is independent of temperature

Subtopic:  Types of Semiconductors |
 88%
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Intrinsic semiconductor is electrically neutral. Extrinsic semiconductor having large number of current carriers would be 

(1) Positively charged

(2) Negatively charged

(3) Positively charged or negatively charged depending upon the type of impurity that has been added

(4) Electrically neutral

Subtopic:  Types of Semiconductors |
 55%
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If ne and vd be the number of electrons and drift velocity in a semiconductor. When the temperature is increased

(1) ne increases and vd decreases

(2) ne decreases and vd increases

(3) Both ne and vd increases

(4) Both ne and vd decreases

Subtopic:  Types of Semiconductors |
 51%
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The energy gap of silicon is 1.14 eV. The maximum wavelength at which silicon will begin absorbing energy is

(1) 10888 Å                   

(2) 1088.8 Å

(3) 108.88 Å                   

(4) 10.888 Å

Subtopic:  Energy Band theory |
 63%
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