Tag: solid state

Quizzes (4) Questions (214)

Questions Related to solid state

Multiple choice chemistry solid state electrical and magnetic properties of solids impurity defects properties of solids

With which one of the following elements silicon should be doped so as to give p-type of semiconductor?

  1. Selenium

  2. Boron

  3. Germanium

  4. Arsenic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The n-type semiconductors are obtained when $Si$ or $Ge$ are doped with elements of group 15, eg, Arsenic $(As)$, while p-type semiconductors are obtained when $Si$ or $Ge$ are doped with traces of group 13 , ie Indium $(In)$ , Boron $(B)$.

So the correct option is $B$.

Multiple choice chemistry solid state electrical and magnetic properties of solids impurity defects properties of solids

Which of the following statement is true about semiconductors?

  1. Impurity of lower group creates $n-$type semiconductors
  2. Impurity of higher group creates $p-$type semiconductors

  3. extrinsic semiconductors are formed by doping impurity

  4. Intrinsic semiconductors become conductors when temperature is raised
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An extrinsic semiconductor is one that has been doped; during manufacture of the semiconductor crystal a trace element or chemical called a doping agent has been incorporated chemically into the crystal, for the purpose of giving it different electrical properties than the pure semiconductor crystal.

So, option $C$ is correct.

Multiple choice chemistry solid state electrical and magnetic properties of solids impurity defects properties of solids

Which of the following is true about the charge acquired by $p-$type semiconductors?

  1. Positive

  2. Neutral

  3. Negative
  4. Depends on concentration of $p$ impurity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$p-$type semiconductors have a larger hole concentration than electron concentration. In p-type semiconductors, holes are the majority carriers and electrons are the minority carriers. $p-$type semiconductors are created by doping an intrinsic semiconductor with acceptor impurities. A common $p-$type dopant for silicon is boron or gallium. There will be no charge on the semiconductor.

So, correct answer is option $B$.

Multiple choice chemistry solid state electrical and magnetic properties of solids impurity defects properties of solids

Which of the following oxides behaves as conductor or insulator depending upon temperature?

  1. $TiO$
  2. $SiO _2$
  3. $TiO _3$
  4. $MgO$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$TiO _{ 3 }$ behaves as conductor or insulator depending on temperature because of variation of energy gap between valence band and conduction band with the variation of temperature.

So, correct answer is option $C$. 

Multiple choice chemistry solid state electrical and magnetic properties of solids impurity defects properties of solids

To get a $n-$type semiconductor from silicon, it should be doped with a substance with valence _______.

  1. 2

  2. 1

  3. 3

  4. 5
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An $n-$type semiconductor is made by adding a small amount of a Group-V element such as phosphorous ($P$) or arsenic ($As$) to the intrinsic semiconductor. Group-V elements have five valence electrons per atom.

So, correct answer is option $D$.

Multiple choice chemistry solid state electrical and magnetic properties of solids impurity defects properties of solids

Statement-I  The conductance through electrons is called n-type conduction and if through positive semi holes it is called p-type conduction.

Statement-II  Doping involves the preparation of semiconductor by the addition of impurities in the intrinsic semiconductor.

  1. Statement-I is correct but Statement-II is wrong

  2. Statement-I is wrong but Statement-II is correct

  3. Both Statement-I and Statement-II are correct and Statement-II is correct explanation of Statement-I

  4. Both Statement-I and Statement-II are correct but Statement-II is not correct explanation of Statement-I
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The conductance through electrons is called n-type conduction and if through positive semiholes, it is called p-type conduction.
Doping involves preparation of semi-conductors by the presence of impurities in the intrinsic semiconductor.With donor impurities, we get n-type semi-conductors and with acceptor impurities, we get p-type semi-conductors.

Thus, the explanation provided was inadequate.

Multiple choice chemistry solid state electrical and magnetic properties of solids impurity defects properties of solids

Select the correct statement(s).

  1. The conductance through electrons is called p-type conduction.

  2. The conductance through positive holes is called p-type conduction.

  3. The conductance through electrons is called n-type conduction.

  4. The band gap in germanium is small.
Reveal answer Fill a bubble to check yourself
B,C,D Correct answer
Explanation

The addition of small amount of foreign impurity in the host crystal is called as doping. It results in an increase in the electrical conductivity of the crystal. Doping of group 14 elements (such as Si, Ge etc.) with elements of group 15 (such as As) produces an excess of electrons in the crystals and thus, gives n-type semiconductors. Doping of groups 14 elements with group 13 elements (such as Indium) produces holes (electron deficiency) in the crystals. Thus, p-type semiconductors are produced. The symbol 'p' indicates flow of positive charge. Also, the band gap in germanium is small as Ge is a semi-conductor.

Multiple choice chemistry solid state electrical and magnetic properties of solids impurity defects properties of solids

Assertion: 

Group-$15$ doped crystals of Si are called n-type semiconductors.
Reason: 
Neutrons are responsible for the semiconducting properties.

  1. Both Assertion and Reason are correct and Reason is the correct explanation of Assertion

  2. Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion

  3. Assertion is correct but Reason is incorrect

  4. Assertion is incorrect but Reason is correct

  5. Both Assertion and Reason are incorrect
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The addition of a small amount of foreign impurity in the host crystal is called doping. 

It increases the electrical conductivity of the crystal. Doping of group 14 elements (such as Si, Ge, etc.) with elements of group 15 (such as As) produces an excess of electrons in the crystals, thus, giving n-type semiconductors. 
Doping of groups 14 elements with group 13 elements (such as Indium) produces holes (electron deficiency) in the crystals. Thus, p-type semiconductors are produced. The symbol 'p' indicates the flow of positive charge.

Thus, Assertion is correct but Reason is incorrect

Hence, the correct option is $\text{C}$