3.2 Flashcards
How can static electricity be produced?
Contact, friction or induction.
What is the formula for current density?
Current density (J) = Current (I) / Cross-sectional area (A)
What must cables not be heated to?
Over 60 Celsius
Where do lines of force terminate?
Where there is an opposite charge.
Why do metals not need an initial charge?
They are riddled with electrons.
Where do electrons flow in metals?
Flow from negative to positive pole.
What leads do the current mostly heat in a filament bulb?
The thin filament to white heat, hardly heats thicker leads
What happens to the heat if the cross sectional area is decreased when pushing a current through?
It is increased.
What is current density formula?
Current density (J) = current (A) / cross sectional area (mm2)
At what ambient temperature is a maximum permitted load specified for each given cable cross sectional area?
25 Celsius
