Rectifiers. Determination of the parameters of low frequency alternating current pulses - Medical Physics -
Description
Medical Physics Quiz on Rectifiers. Determination of the parameters of low frequency alternating current pulses - Medical Physics - , created by Hussain Basheer on 23/11/2018.
What particles are the electric current carriers (charge carriers) in metals?
Answer
Electrons
Ions
Electrons and holes
Question 3
Question
For the photoelectric effect to take place, the wavelength (λ) of the incident light must satisfy the following inequality:
Where: ɸ is the minimum energy needed to remove an electron from metal (work function); h is Plank constant.
Answer
λ ≥ ɸ/h
λ ≤ hc/ ɸ
λ ≥ c/ɸ
Question 4
Question
Electric current is measured in units of amps (A) which represent the following rate of change:
Answer
Charge per time, Q/t
Energy per charge, E/Q
Energy per distance, E/x
Question 5
Question
Alternating current (AC):
Answer
Changes frequency with time
Changes power with time
Changes direction with time
Question 6
Question
The Oscilloscope measures and displays the relationship between two variables, input (y-axis) andreference (x-axis). Choose the correct pair:
Answer
Time (input) vs Voltage (reference)
Voltage (input) vs Time (reference)
Current (input) vs Voltage (reference)
Question 7
Question
The current carriers inside vacuum tubes are:
Answer
Electrons
Ions
Electrons and holes
Question 8
Question
The term ”charge carrier” refers to
Answer
Strictly to electrons and holes
Strictly to electrons and protons
Any particle that has an electric charge
Question 9
Question
The term ”elementary charge“ refers to
Answer
The charge of the electron
The charge of any charge carrier
The charge of any elementary particle
Question 10
Question
If across 25Ohm resistor is applied 50V (DC) how many Amperes is the current that will flow:
Answer
20 mA
0.5 A
2 A
Question 11
Question
What happens to the current (DC) in metallic conductor, if the voltage is doubled?
Answer
It will be halved
It will double
It will stay the same
Question 12
Question
Ohm’s Law states that the magnitude of the electric current is proportional to the applied voltage and inversely proportional to the resistance in the conducting material. Choose one:
Answer
I = V/R
I = R/V
I =V·R
Question 13
Question
For Ohmic load in a DC circuit, what would be the change in power consumption if the voltage is halved?(hint: in Ohmic circuits the ratio V/I = constant, and power = V·I)
a. It will double
Answer
It will double
It will be halved
It will be quartered
Question 14
Question
What is the resistance in a load if, when 120 V are applied, it draws a current of 20 Amps:
Answer
6 Ohms
60 Ohms
100 Ohms
Question 15
Question
Metals are good conductors of electricity because:
Answer
There are free electrons
There are free electrons and protons
There are electrons and positrons
Question 16
Question
A 400 Ohm resistor draws 0.05 A direct current. What is the voltage across the resistor