Electrical Engineering Quiz

A transformer has an input power of 20kW and power losses of 920W, the overall efficiency is

• a) 9.4%

• b) 94.5%

• c) 95.4%

• d) 9.5%

What is this component?

• a) A transistor

• b) A triac

• c) A diac

• A thyristor

An arrow appearing through an electronic symbol means the device is:

• a) Preset

• b) Light emitting

• c) Variable

• d) Fixed

A conductor is placed in a static magnetic field and a current is passed through it. The force exerted on it can be calculated by

• a) F = BLV

• b) F = BIL

• c) F = ma

• d) F = mg

M_ is the abbreviation used for:

• a) Microhms

• b) Milli-Ohms

• c) Megohms

• d) Meggerohms

A length of copper wire has resistance 8 Ω. What would be the resistance if the length was halved and the cross sectional area doubled:

A 9V battery is connected across a set of resistors in series, values being: 3 Ω, 12 Ω, 160Ω and 68 Ω. The current flowing in the circuit is:

• a) 233A

• b) 2097A

• c) 25.89A

• d) 37mA

A power supply has four diodes connected in ‘bridge’ after the transformer. Is this called a:

• Half wave rectifier

• Full wave rectifier

• Full wave smoother

• Half wave smoother

What is this rule and where is it used?

• Left hand rule, motors

• Right hand rule, generators

• Left hand rule, generators

• Right hand rule, motors

What is the SI unit for magnetic flux?

• Tesla

• Coulomb

• Angstrom

• Weber