Tag: semiconductors

Questions Related to semiconductors

Production of ICs is preferred in industrial scales because:

physics semiconductors integrated circuits & microprocessor integrated chips semiconductor devices

  1. it reduces the cost of production.

  2. it makes the task of fabrication of a circuit easier.

  3. it improves the efficiency of the circuit.

  4. specifications of a circuit is same for all applications.

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Correct Option: A
Explanation:

Integrated circuits are electronic circuits formed on a small piece of semiconducting material, which perform the same function as a larger circuit made from discrete components. They are compact, and cheap and fast and more efficient than conventional circuits. Due to their low cost of production on large scales they are produced on industrial scale.

Which of the following is an advantage of a conventional circuit over integrated circuit?

physics semiconductors integrated circuits & microprocessor integrated chips semiconductor devices

  1. They are fast.

  2. They have higher power handling capability.

  3. They are large in size.

  4. All of the above.

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Correct Option: B
Explanation:

Integrated circuits are electronic circuits formed on a small piece of semiconducting material, which perform the same function as a larger circuit made from discrete components. They are compact, and cheap and fast and more efficient than conventional circuits, and hence they are preferred over them. However conventional circuits still have the advantage of high power handling capacity over the ICs.

Choose the correct statements:

physics semiconductors integrated circuits & microprocessor integrated chips semiconductor devices

  1. It is easier to fabricate $10000$ AND gates using circuit components than on an integrated chip.

  2. It is easier to fabricate $10000$ AND gates on an integrated chip than fabricating them using circuit components.

  3. It is easier to fabricate a single AND gate using circuit components as compared to on an IC.

  4. It is easier to fabricate a single AND gate on an IC as compared to using circuit components.

Show answer
Correct Option: B,C
Explanation:

Integrated chips have advantage when being used to fabricate a number of components at the same time. However when single component is being fabricated, it is advisable to fabricate components using circuit components instead of an Integrated Circuit.

Choose the correct statement:

physics semiconductors integrated circuits & microprocessor integrated chips semiconductor devices

  1. Integrated circuits are less efficient in performance at all voltages.

  2. Integrated circuits are more efficient in performance at low voltages.

  3. Integrated circuits are less efficient in performance at high voltages.

  4. Performance of an integrated circuit is independent of the magnitude of applied voltage.

Show answer
Correct Option: B
Explanation:

Integrated circuits are used for low voltage applications. They are low power devices for use in application like microprocessor chips. 
For high voltage devices like transformers, conventional circuits are used.

Which of the following is not an advantage of Integrated Circuits (ICs).

physics semiconductors integrated circuits & microprocessor integrated chips semiconductor devices

  1. Extremely small in size

  2. High power consumption

  3. Low cost

  4. Less weight

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Correct Option: B
Explanation:

Advantages:
i) Extremely small in size,
ii) Low power consumption,
iii) Reliability,
iv) Low cost,
v) Less weight,
vi) Easy replacement.

Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to $(E _g) _C,\, (E _g) _{Si}$ and $(E _g) _{Ge}$.Which of the following statements is true?

physics semiconductors band theory of solids, a brief introduction electron energies in solids energy bands

  1. $(E _g) _{Si}\, <\, (E _g) _{Ge}\, <\, (E _g) _C$

  2. $(E _g) _{C}\, <\, (E _g) _{Ge}\, >\, (E _g) _{Si}$

  3. $(E _g) _{C}\, >\, (E _g) _{Si}\, >\, (E _g) _{Ge}$

  4. $(E _g) _{C}\, =\, (E _g) _{Si}\, =\, (E _g) _{Ge}$

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Correct Option: C
Explanation:
For given elements, the energy band gap of carbon is the maximum and of germanium is the least.
Hence option C is correct.

The band gap is larger for which of the following 

physics semiconductors band theory of solids, a brief introduction electron energies in solids energy bands

  1. Conductor

  2. Insulator

  3. Semiconductor

  4. None of the above

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Correct Option: B
Explanation:

In conductors, the conduction band is partially filled or overlapped with valance band.

In semiconductors, the band gap is small.
In insulators, the band gap is largest.

The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $2480\ nm$ is incident on it. The band gap in $(eV)$ for the semiconductor is.

physics semiconductors band theory of solids, a brief introduction electron energies in solids energy bands

  1. $0.5\ eV$

  2. $0.7\ eV$

  3. $1.1\ eV$

  4. $2.5\ eV$

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Correct Option: A

The difference between the highest energy in a band and lowest energy in the next higher band is called the band gap between the two energy bands.

physics semiconductors band theory of solids, a brief introduction electron energies in solids energy bands

  1. True

  2. False

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Correct Option: A

In extrinsic semiconductors :

physics semiconductors band theory of solids, a brief introduction electron energies in solids energy bands

  1. the conduction band and valence band overlap

  2. the gap between conduction band and valence band is near about $16\ eV$

  3. the gap between conduction band and valence band is near about $ 1\ eV$

  4. the gap between conduction band and valence band will be $100\ eV$ and more

Show answer
Correct Option: C
Explanation:

In extrinsic semiconductors, formation of donor or acceptor level takes place in forbidden energy gap. Thus, some of the electrons in valance band acquire enough energy to jump to donor level or acceptor level present in forbidden energy gap. Thus, to obtain large number of electrons in conduction band some energy to be supplied to the electrons in valance band. For extrinsic semiconductors, it is nearly equal to $1\ eV$.