Energy Graph Diagram

Q. The forbidden energy band gap in conductors, semiconductors and insulators is $E{G}_1,E{G}_2\mathrm{and}E{G}_3$ respectively. The relation among them is

1. $E{G}_1=E{G}_2=E{G}_3$
2. $E{G}_1<E{G}_2<E{G}_3$
3. $E{G}_1>E{G}_2>E{G}_3$
4. $E{G}_1<E{G}_2>E{G}_3$

Q.

In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of

1. 

2. 

3. 

4. 

Q. Why potential barrier increases on increase temperature?

Q.

The probability of electrons to be found in the conduction band of an intrinsic semiconductor at a finite temperature

1. Decreases exponentially with increasing band gap

2. Increases exponentially with increasing band gap

3. Decreases with increasing temperature

4. Is independent of the temperature and the band gap

Q. Monochromatic radiation emitted when electron onhydrogen atom jumps from first excited to the groundstate irradiates a photosensitive material. Thestopping potential is measured to be 3.57 V Thethreshold frequency of the material is

Q.

In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of

1. 

2. 

3. 

4. 

Q. What is the resistance of an intrinsic semiconductor at 0 K?

Q.

Thermionic emission from a heated filament varies with its temperature T as

1. 

2. 

3. 

4. 

Q. The distinction between conductors, insulators and semiconductors is largely concerned with

1. their ability to conduct current
2. the type of crystal lattice
3. binding energy of their electrons
4. relative widths of their energy gaps

Q.

Three semi-conductors are arranged in the increasing order of their energy gap as follows. The correct arrangement is :

1. Tellurium, germanium, silicon

2. Tellurium, silicon, germanium

3. Silicon, germanium, tellurium

4. Silicon, tellurium, germanium

Q. A $\text{p - n}$ photodiode is fabricated from a semiconductor with band gap of $2.8\text{eV}$. Which of the following wavelengths cannot be detected ?

1. $6000\text{nm}$
2. $60\text{nm}$
3. $420\text{nm}$
4. $100\text{nm}$

Q.

The probability of electrons to be found in the conduction band of an intrinsic semiconductor at a finite temperature

1. Decreases exponentially with increasing band gap

2. Increases exponentially with increasing band gap

3. Decreases with increasing temperature

4. Is independent of the temperature and the band gap

Q.

Three semi-conductors are arranged in the increasing order of their energy gap as follows. The correct arrangement is :

1. Tellurium, germanium, silicon

2. Tellurium, silicon, germanium

3. Silicon, germanium, tellurium

4. Silicon, tellurium, germanium

Q. Which of the following must be there in materials that make good electrical insulators?

1. high conductivity
2. low conductivity
3. very few, if any, free electrons
4. more than 10 electrons
5. energetic electrons

Q. Which of the following statement(s) is/are correct?

1. Conductors are materials that allow the flow of electric current, whereas dielectric (insulators) do not
2. The main difference between conductor and dielectric behavior is the amount of available free electrons
3. Not all conductors have the same level of conductivity, just as not all insulators are resistant to electric current.
4. Both A and B only

Q. Energy band at a higher level is called ________ .

1. valance band
2. energy gap
3. conduction band
4. energy band

Q.

Three semi-conductors are arranged in the increasing order of their energy gap as follows. The correct arrangement is :

1. Tellurium, silicon, germanium

2. Tellurium, germanium, silicon

3. Silicon, germanium, tellurium

4. Silicon, tellurium, germanium

Q.

1. 
   

2. 
   

3. 
   

4. 
   

Q.

Thermionic emission from a heated filament varies with its temperature T as

1. 
   

2. 
   

3. 
   

4.