ELECTRONIC DEVICES

1 )

C, Si and Ge have same no. of valence electrons. C is an insulator because energy required to take one electron out from

Si is more

C is more

Ge is more

C is less

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Answer :

C is an insulator. Energy required to take one electron out from C is more.

2 )

Ionization energy of isolated phosphorous atom 10 eV. Ionization energy of same atom in Si is nearly ________ eV (Relative Permittivity of silicon = 12)

0.1

0.2

0.3

0.4

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Answer :

Ionization of isolated phosphorus = 10 eV

When phosphorus is in Si atom then out of 5 valence electron, 4 are

shared with Si. 5^th electron will revolve around nucleus.

situation is like H atom, from which energy is En and

En = [{– 13.6} / n²] eV

for n = 1, En = – 13.6 eV

Energy inside the lattice = (En / E²) = {(– 13.6) / (12)²} = |0.09| = 0.1 eV

3 )

By adding _______ impurity in intrinsic semiconductor P type semiconductor is made. Charge of these P type semiconductor is ______

trivalent, neutral

pentavalent, neutral

pentavalent, positive

trivalent, negative

View Solution

Answer :

Trivalent impurities form P-type semiconductor. And it is neutral material.

4 )

Strong overlapping of different atomic orbital's makes

different energy level

energy band

Conductor

Insulators

View Solution

Answer :

Strong overlapping of different atomic orbital make energy bands.

5 )

We cannot make p – n junction diode by making P type semi-conductor join with N-type semi-conductor, because

Inter-atomic spacing becomes less than 1 A°

P-type will repel N-type

There will be discontinuity for the flowing charge carriers

semi-conducting properties will be lost

View Solution

Answer :

There will be discontinuity for the flowing charge carriers By this way, there will be discontinuity for the flowing charge carrier.

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