Charge, current and Energy, power and resistance

Question 1

Kirchoffs first law

Answer 1

Sum of current entering a junction in a circuit equals to the sum of the current leaving the circuit.

Question 2

electron drift velocity equation

Answer 2

I=Anev

Question 3

what is the emf

Answer 3

The energy gained per unit charge

Question 4

Ohms law

Answer 4

current through a conductor is directly proportional to the potential difference across it.

Question 5

factors that affect electrical resistance

Answer 5

• material of wire
• length of wire-electrical resistance increases as length increases
• temperature of wire-when temperature increases, kinetic energy of metal atoms, so resistance increases

Question 6

I-V characteristics of a resistor

Answer 6

current is directly proportional to potential difference

Question 7

I-V characteristics of a filament lamp

Answer 7

at low temperature ti behaves with accordance to ohms law, but as temperature increases due to current increase, it is not a linear proportion.

Question 8

I-V characteristics of a diode

Answer 8

Diode only allows current to flow in one direction, so no current can pass through the other direction,
so it is to be thought it has almost an infinite resistance.