Hussain Basheer
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Medical Physics Quiz on Transformation of non-electrical quantities. Calibration of semiconductor, thermometer and photoelement - Medical Physics - MCQs, created by Hussain Basheer on 23/11/2018.

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Hussain Basheer
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Transformation of non-electrical quantities. Calibration of semiconductor, thermometer and photoelement - Medical Physics - MCQs

Question 1 of 24

1

If a semiconductor is brought down to temperature of absolute zero (0 Kelvin), it will become:

Select one of the following:

  • A conductor

  • A superconductor

  • An insulator

Explanation

Question 2 of 24

1

According to Band Theory of Solids, what can be said about the relationship between band-gap width and the tendency of material to conduct electricity?

Select one of the following:

  • The greater the band-gap width the less conductive is the material

  • The lesser the band-gap width the more insulating is the material

  • The greater the band-gap width the more conductive is the material

Explanation

Question 3 of 24

1

According to Band Theory of Solids, what can be said about P- and N- type conductivity with regard to the location of the electron bands?

Select one of the following:

  • P and N type conductivities are in the conduction band

  • P-type conductivity is in the conduction band, and N-conductivity is in the valence band

  • P-type conductivity is in the valence band, and N-conductivity is in the conduction band

Explanation

Question 4 of 24

1

What are the respective current carriers for N- and P-type conductivity?

Select one of the following:

  • Electrons

  • P-type carriers are “holes”, and N-type are electrons

  • P-type are positrons, and N-type are “holes”

Explanation

Question 5 of 24

1

Typical semiconductors such as Silicon and Germanium are group IV elements. Choose the correct statement regarding the doping and the type of conductivity (N or P) acquired, after doping:

Select one of the following:

  • P-type conductivity is achieved by doping with elements from group V, and N-type conductivity is achieved by doping with elements from group III

  • Both types are achieved from doping with group IV

  • P-type conductivity is achieved by doping with elements from group III, and N-type conductivity is achieved by doping with elements from group V

Explanation

Question 6 of 24

1

What is the relationship between N- and P- type charge carriers for intrinsic (undoped) semiconductors?

Select one of the following:

  • N = P

  • N > P

  • N < P

Explanation

Question 7 of 24

1

For semiconducting materials, charge carrier species called holes are best described as:

Select one of the following:

  • Electrons moving in opposite direction

  • Protons

  • Virtual particles signifying electron vacancy

Explanation

Question 8 of 24

1

In doped (extrinsic) semiconductors, the predominant current carriers are called majority charge carriers, and secondary carriers are called minority. Which statement is true for N-and P-type semiconductors:

Select one of the following:

  • In N-type semiconductors, electrons are majority carriers and holes are minority carriers

  • In P-type semiconductors, majority carriers are electrons, and minority charge carriers are holes

  • In N-type semiconductors, both types of carriers are equally present

Explanation

Question 9 of 24

1

Transistors are made of N- and P-type semiconductors arranged in a such way that:

Select one of the following:

  • There are two p-n junctions

  • There are three p-n junctions

  • There is one p-n junction

Explanation

Question 10 of 24

1

The two main functions of the transistor are:

Select one of the following:

  • Polarizer and oscillator

  • Amplifier and switch

  • Rectifier and attenuator

Explanation

Question 11 of 24

1

Choose the FALSE statement. Electrical amplifiers are used for:

Select one of the following:

  • Voltage

  • Frequency

  • Current

Explanation

Question 12 of 24

1

The magnitude of electrical impedance of biological tissues is the (Pythagorean) sum of:

Select one of the following:

  • Resistance and capacitive reactance

  • Inductive and capacitive reactance

  • Resistance and inductive reactance

Explanation

Question 13 of 24

1

What type of transducer is the piezoelectric crystal in ultrasonic equipment, when working in receiving mode?

Select one of the following:

  • Generative transducer

  • Both, generative and parametric

  • Parametric transducer

Explanation

Question 14 of 24

1

The “band gap” in semiconductor theory is defined as:

Select one of the following:

  • The distance between valence and conduction bands

  • The frequency gap between AM and FM radio bands

  • The energy gap between valence and conduction bands

Explanation

Question 15 of 24

1

When temperature increases, the band gap in a semiconductor:

Select one of the following:

  • Increases, due to increased kinetic energy of atoms

  • Remains the same, because electrons are bound in their orbits

  • Decreases, due to electron-phonon interactions

Explanation

Question 16 of 24

1

When semiconductor is doped with element of lower valence (P-type doping) it becomes a donor (gives off electrons) and there is a shift in the energy band gap. The new electron levels are:

Select one of the following:

  • Near the middle of the band gap

  • Near the conduction band

  • Near the valence band

Explanation

Question 17 of 24

1

When temperature increases, the conductivity of semiconductors:

Select one of the following:

  • Increases

  • Decreases

  • Remains the same

Explanation

Question 18 of 24

1

When semiconductor is doped with element of higher valence (N-type doping) it becomes an acceptor (takes electrons) and there is a shift in the energy band gap. The new electron levels are:

Select one of the following:

  • Near the middle of the band gap

  • Near the conduction band

  • Near the valence band

Explanation

Question 19 of 24

1

When Silicon (Si) is doped with one of the following elements, it acquires P-type conductivity (holes are the majority carriers). Choose the one:

Select one of the following:

  • Boron (B), valence III

  • Phosphorus (P), valence V

  • Tin (Sn), valence IV

Explanation

Question 20 of 24

1

Electric circuit components composed of single p-n junction are called:

Select one of the following:

  • Capacitors

  • Transistors

  • Diodes

Explanation

Question 21 of 24

1

What is the mathematical relation between the electrical resistance (R) in a semiconductor and the temperature (T)?

Select one of the following:

  • Linear (as T increases, R decreases with constant rate)

  • Proportional (as T increases, R increases with constant rate)

  • Exponential decay (as T increases, R decreases with increasing rate)

Explanation

Question 22 of 24

1

What is the mathematical relationship between the generated voltage in a photodiode and the distance from the light source?

Select one of the following:

  • Quadratic (voltage increase as the square of the distance)

  • Inversely proportional (decreases as one over the distance)

  • Exponential (increases with increasing rate)

Explanation

Question 23 of 24

1

Which of the following statements is true about the element Germanium?

Select one of the following:

  • The resistivity at room temperature is lower than that of Copper

  • When heated the resistivity decreases

  • The resistivity is constant over a wide range

Explanation

Question 24 of 24

1

The most common material in modern integrated circuits is:

Select one of the following:

  • Silicon

  • Carbon

  • Titanium

Explanation

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