Electrical scientific principles resistance & resistivity

V=IR, make I the subject

• I = V/R

• I = VR

• I = R/V

• I = (R X R) X V

What is the SI quantity of ohms

• Power

• Current

• Resistance

• Voltage

If a mass of 9850g is raised a distance of 15m calculate the amount of work done to the nearest newton meter.

• 657Nm

• 1356Nm

• 1450Nm

• 1449Nm

Calculate the power used when an object moves a distance of 25m in 12 seconds by a force of 65N

• 135.42W

• 31.2W

• 19.5W

• 4.62W

Calculate the resistance of single copper cable this is 125m long and has a CSA of 25mm. Take the resistivity of copper to be 1.72 x 10 (-8)) ohm/meters.

• 4.13 ohms

• 0.086 ohms

• 1.82 ohms

• 3.44 ohms

If you have a cable with a resistance of 0.55, a CSA of 4mm² and a resistivity of 1.72 x 10 (-8) what would the length of cable be?

• 127

• 158

• 137

• 128

What is the current flowing in a circuit when a voltage of 227v is present across a resistance of 18 ohms?

• 12.61A

• 4086A

• 0.079A

• 0.70A

A cable with a resistance of 0.057 ohms carries 101.6A what will the voltage drop be in the cable?

• 1782.46v

• 5.79v

• 0.33v

• 588.39v

Calculate the value of a resistor to be connected in series with two series connected resistors each of 3.6Ω and 5.7Ω to give a total resistance of 12.3Ω

• 8Ω

• 3.05Ω

• 3Ω

• 8.78Ω

How many resistors of 0.45Ω must be connected in a series to give a total resistance of 8.1Ω

• 9Ω

• 36Ω

• 18Ω

• 0.45Ω