# Basic Electronics Engineering Questions and Answers – Transducers – Resistance Thermometer and Hall Effect – Set 2

This set of Basic Electronics Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Transducers – Resistance Thermometer and Hall Effect – Set 2”.

1. In hall effect the produced electric field is in the direction perpendicular to _________
a) Magnetic field
b) Current
c) Magnetic field and electric field
d) Magnetic field and current

Explanation: When a magnetic field B, is applied to a current carrying conductor or semiconductor of current I, then the induced electric field E is in the direction perpendicular to both B and I is called as hall effect.

2. The hall effect is used to find the semiconductor is weather a P type or N type.
a) False
b) True

Explanation: The Hall Effect has many applications. One of the most important application of the hall effect is to find out whether the semiconductor is a P type or N type semiconductor. By applying magnetic field we can find it.

3. The hall parameter increases with increase in _________
a) Magnetic field
b) Current
c) Electric field
d) Number of holes

Explanation: The hall parameter increases with an increase of the magnetic field applied to the semiconductor that is B. Generally, the hall parameter is very inferior to unity.

4. The mobility can be calculated by simultaneous measurement of __________
a) Conductivity
b) Conductance
c) Inductance
d) Resistivity

Explanation: The mobility μ of the electrons or holes of the semiconductor can be calculated by the simultaneous measurement of conductivity σ. The magnetic field and current flow pertaining the Hall Effect are arranged schematically.

5. An electron charge e travelling in a magnetic field B, with drift velocity V experiences a force given by ________
a) F=e.E
b) F=E.B
c) F=e.B
d) F=B.b

Explanation: The electron charge e travelling in a magnetic field B, with drift velocity V experiences a force given by F=e.E, here F is the force, E is the electric field and e is the electric charge then electric field E can be given by the product of magnetic field and drift velocity E=B.V. So, that F=B.e.V.

6. The hall voltage can be given by _____
a) VH=(RHBW)/I
b) VH=(RHWI)/B
c) VH=(RHBI)/W
d) VH=(RHB)/I

Explanation: The hall voltage can be given by VH=(RHBI)/W where VH is the hall voltage. RH=1/ρ, where ρ is called charge density, B=magnetic field and I=current density and the I is the current and ρ=n.e where n=electron concentration.

7. The relation between the charge density and conductivity is given by ____
a) σ=ρ+μ
b) σ=ρ – μ
c) σ=ρ/μ
d) σ=ρ.μ

Explanation: The relation between the charge density and conductivity is given by σ=ρ.μ, where σ=conductivity, ρ=charge density and μ=mobility of the electrons or holes. We can also derive this as we know that mobility is the ratio of the conductivity to the charge density.

8. Hall effect transducers are the non-contact devices with the _________
a) high resolution
b) Low resolution
c) Large size
d) No resolution

Explanation: Hall effect transducers are the non-contact devices with high resolution. They have low size. Other applications are in measurement of velocity, rpm, sorting, limit sensing etc.

9. The hall parameter in the form of angle is given by _______
a) β = tan θ
b) β = cos θ
c) β = sin θ
d) β = cot θ

Explanation: The hall parameter in the form of angle is given by β = tan θ where the β=hall parameter, θ=angle. The angle is made by the two vectors J and E. This is also called as hall angle.

10. Hall probes are used as _______
a) Electro meters
b) Magnetometers
c) Electro magnets
d) Magnets

Explanation; The hall probes are used ad magnetometers. It is used to measure the magnetic fields or to inspect the materials using the principle of magnetic flux leakage. The magnetic flux is given by the number of lines passing through the unit area.

11. The sensing of wheel rotation is used in _________
a) Anti-locking breaking system
b) Electric motors
c) Hydraulic valves
d) Dc motors

Explanation: The sensing of wheel rotation is used in the anti locking breaking system. The principles of such system have been extended and refined to anti skid functions.

12. Corbino effect is the effect that involves the Hall Effect.
a) False
b) True

Explanation: Corbino effect is based on the Hall Effect. In Hall Effect a rectangular metal is used but in corbino effect a disc shaped metal is used instead. Because of the disc the Hall Effect is observed without hall voltage.

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