Electrical Science and principles

The SI unit of mass is the:

• kilogram or kg

• pound or lb

• metre or m

• millimetre or mm

The SI unit of electrical charge is the:

• ohm

• joule

• watt

• coulomb

Area is represented by:

• kg

• m²

• m³

• m

A shower unit draws 20 A from a domestic 230 V supply. Calculate the amount of power used.

• 4.6kW

• 11.5kW

• 46kW

• 0.08kW

Rearrange the formula R = p L/A to find p.

• p = R/LA

• p = RA/L

• p = RL/A

• p = A/RL

A 12 Ω filament lamp was found to be taking a current of 2 A at full brilliance. The voltage across the lamp under these conditions is:

• 6V

• 12V

• 24V

• 48V

The resistance of a kettle element which takes 12 A from a 230 V mains supply is:

• 2.88 Ω

• 5.00 Ω

• 12.24 Ω

• 19.16 Ω

Calculate the energy generated when a circuit is supplied with 100 V, and a current of 2 amperes flows for 6 minutes.

• 72 KJ

• 1.2 KJ

• 12 KJ

• 7000 J

Domestic wiring uses what kind of insulation material?

• Mica

• PVC

• Mineral oxide

• Glass

Good insulator materials include:

• Copper

• PVC

• mica

• mineral oxide