Revision Eleck

From a 50 metre cable drum, you have installed 13.6 metres of cable. What percentage of cable has been used?

• 72.8%

• 3.8%

• 27.2%

• 65%

An insulation resistance tester is used to record the following values: 55MΩ, 72MΩ, 55MΩ, 18.5Ω, 10 MΩ and 89MΩ. What is the mean of

these values?

• 49.9MΩ

• 89MΩ

• 55MΩ

• 18.5MΩ

The SI unit for resistivity is?

• Ohm

• Ωm

• R

• Ω

Potential Difference is measured in?

• Amps

• Volts

• Newton’s

• Joule’s

A 2.5mm 2 copper conductor has a resistance of 1.5 Ohms. If the conductor’s length is doubled what would the resulting resistance be?

• 6 Ohms

• 1.5 Ohms

• 3 Ohms

• 0.3 Ohms