# Electronic Devices and Circuits Questions and Answers – The Hall Effect

This set of Electronic Devices and Circuits Multiple Choice Questions & Answers (MCQs) focuses on “The Hall Effect”.

1. In the Hall Effect, the directions of electric field and magnetic field are parallel to each other.
The above statement is
a) True
b) False

Explanation: To make Lorentz force into the effect, the electric field and magnetic field should be perpendicular to each other.

2. Which of the following parameters can’t be found with Hall Effect?
a) Polarity
b) Conductivity
c) Carrier concentration
d) Area of the device

Explanation: The Hall Effect is used for finding the whether the semiconductor is of n-type or p-type, mobility, conductivity and the carrier concentration.

3. In the Hall Effect, the electric field is in x direction and the velocity is in y direction. What is the direction of the magnetic field?
a) X
b) Y
c) Z
d) XY plane

Explanation: The Hall Effect satisfies the Lorentz’s Force which is
E=vxB
So, the direction of the velocity, electric field and magnetic field should be perpendicular to each other.

4. What is the velocity when the electric field is 5V/m and the magnetic field is 5A/m?
a) 1m/s
b) 25m/s
c) 0.2m/s
d) 0.125m/s

Explanation: E=vxB
v=E/B
=5/5
=1m/s.

5. Calculate the hall voltage when the Electric Field is 5V/m and height of the semiconductor is 2cm.
a) 10V
b) 1V
c) 0.1V
d) 0.01V

Explanation: Vh=E*d
=5*2/100
=0.1V.

6. Which of the following formulae doesn’t account for correct expression for J?
a) ρv
b) I/wd
c) σE
d) µH

Explanation: B=µH
So, option µH is correct option.

7. Calculate the Hall voltage when B=5A/m, I=2A, w=5cm and n=1020.
a) 3.125V
b) 0.3125V
c) 0.02V
d) 0.002V

Explanation: Vh=BI/wρ
=5=2/ (5*10-2*105*1.6*10-19)
=0.002V.

8. Calculate the Hall Effect coefficient when number of electrons in a semiconductor is 1020.
a) 0.625
b) 0.0625
c) 6.25
d) 62.5

Explanation: R=1/ρ
=1/(1.6*10-19*1020)
=0.0625.

9. What is the conductivity when the Hall Effect coefficient is 5 and mobility is 5cm2 /s.
a) 100 S/m
b) 10 S/m
c) 0.0001S/m
d) 0.01 S/m

Explanation: µ=σR
σ =µ/R
=5*10-4/5
=0.0001 S/m.

10. In Hall Effect, the electric field applied is perpendicular to both current and magnetic field?
a) True
b) False

Explanation: In Hall Effect, the electric field is perpendicular to both current and magnetic field so that the force due to magnetic field can be balanced by the electric field or vice versa.

Sanfoundry Global Education & Learning Series – Electronic Devices and Circuits.

To practice all areas of Electronic Devices and Circuits, here is complete set of 1000+ Multiple Choice Questions and Answers.