WorksheetsLesson 1 Unit 8 Electronic Principles
Total questions: 20
Worksheet time: 12mins
The magnetic saturation of a material is approximately 1.5T. Is the material:
Iron
Copper
Steel
Aluminium
Electricity is concerned with the movement of:
Neutrons
Molecules
Atoms
Electrons
Fleming’s left-hand rule is best described as:
First finger current, second finger field, thumb, force – describing generators
First finger field, second finger current, thumb force – describing motors
First finger field, second finger current, thumb force – describing generators
First finger force, second finger current, thumb field – describing motors
What is best described as a joules per second?
Amps
Coulombs
Volts
Watts
A power of 500W is dissipated in a resistor of 35Ω. What is the current and voltage?
3.78A and 132.29V
3.78A and 134.12V
3.76A and 132.29V
3.78A and 132.58V
The energy stored in an inductor is 250mJ and the current is 5A. What is the inductance of the coil?
35mH
30mH
25mH
20mH
Consider the following illustration. What is the value of I4?
Consider the following circuit. What is the value of R1?
20Ω
10Ω
15Ω
25Ω
Consider the following circuit. Calculate the current through the 10Ω resistor.
4.65A
3.34A
2.97A
3.87A
A 100uF capacitor is connected in series with a resistor of 25Ω across a DC supply voltage. What is the time constant of the circuit?
1.5ms
2.5ms
2ms
1ms
An inductor of 150mH is connected in series with a 50Ω resistor across a 200V supply. Calculate the current after 4ms.
3.52A
3.62A
2.95A
2.65A
A 150uF capacitor is connected in series with a 50Ω resistor across a supply voltage of 150V. Calculate the time it takes the value of current to drop to 2A.
0.5 seconds
1.5 seconds
2.5 seconds
3.5 seconds
In an AC series circuit the value of inductive reactance (XL) is 25Ω and the value of capacitive reactance (XC) is 30Ω. Is the circuit current:
Lagging
Leading
In phase
Not enough data to determine
In an AC series circuit R = 40Ω, C = 200uF, L = 0.15H. The components are connected across a 240V AC supply at 50Hz. Calculate the value of the current.
4.73A
5.42A
3.25A
6.85A
If the current phasor is rotating behind the voltage phasor by 30 degrees, what is the power factor of the circuit?
0.577 lag
0.5 lead
0.866 lead
0.866 lag
When a diode is forward-biased, the potential difference across it is typically:
1.0V
0V
0.7V
0.1V
A npn transistor requires the following conditions to turn on:
The base -ve compared to the emitter
The base +ve compared to the collector
The base -ve compared to the collector
The base +ve compared to the emitter
Why must water purity be monitored on a water cooled transistor?
To make sure it has a low resistance
To avoid minerals building up in the cooling system
If you were protecting a high voltage installation from lightning strikes, what would you use?
RCD
Overcurrent inverse time relay
Distance relay
Spark gap arrester
What devices would help connect a pressure transducer to a computer?
P/I connected to an A/D, connected to the computer
V/I connected to an A/D, connected to the computer
P/I connected to a D/A, connected to the computer
A/D connected to a A/D, connected to the computer
