Electrical science 2

A 5 Ohm resistor and a 7 Ohm resistor are wired in series and connected to a 25 volt supply.

What is the power dissipated in the 7 Ohm resistor?

• 52 Watts

• 57 Watts

• 89 Watts

• 30 Watts

A copper conductor is forty meters long and has a c.s.a of 6mm².

If the conductor material was changed to aluminium the resulting resistance would be:

• The same

• Lower

• Higher

• Unstable

Which statement is correct with regards to what makes a good insulator?

• The electrons are tightly bound to the nucleus

• The electrons are loosely bound to the nucleus

• The protons are tightly bound to the nucleus

• The protons are loosely bound to the nucleus

Which of the following materials is a good conductor of electricity?

• Air

• Tungsten

• Glass

• Sand

Which effect would make a Fuse blow?

• Chemical

• Magnetic

• Thermal

• Solar

What is the total combined resistance of the resistors show in the figure below?

• 35 Ohms

• 11.6 Ohms

• 2.9 Ohms

• 4.5 Ohms

What is the missing voltage value in the figure below?

• 25 Volts

• 12.5 Volts

• 50 Volts

• 27.5 Volts

A 16 Amp motor is connected to a cable with a very high resistance.

Which of the following issues would occur?

• The motor will pull more current than it is designed to pull and damage itself

• Too much voltage will appear at the motor terminals damaging the motor

• There will be not enough voltage to operate the motor

• The motor would run in reverse

An aluminium conductor has a resistance of 0.88 Ohm’s and a c.s.a of 1.5mm².

How long is the conductor if it’s resistivity is 2.84x10^-8 Ωm?

• 46.5 M

• 23 M

• 34.5 M

• 62 M

Magnetic Flux Density is defined by:

• the measurement of quantity of magnetic flux

• the amount of flux in a given area

• the strength of a magnetic

• the magnets north and south poles