Chapter 9.5 I-V Characteristics

Question 1

What is a filament lamp

Answer 1

Electrical component containing narrow filament of wire that transfers electrical energy into heat + light

Question 2

I-V characteristic definition

Answer 2

• Description of relationship between electric current in component and potentional difference across it

• Usually graph of I against V
-Resistance is gradient inverse

Question 3

What is the I-V characteristic for a resistor

Answer 3

• Potential difference across resistor is directly proportional to current in resistor

• Resistor obeys Ohm’s law
-ohmic conductor

• Resistance is constant
• Behaves same way regardless of polarity

Question 4

What is the I-V characteristic for a filament lamp

Answer 4

• Potential difference is not directly proportional to current

• Filament lamp does not obey Ohm’s law
-non-ohmic component

• Resistance is not constant
• Behaves same way regardless of polarity

• Resistance increases as pd across it increases
-found by V/I using graph

• Caused by wire getting hot.

• current increases
• more collisions between electrons and positive metal ions per second
• transfer energy to ions, causing ions to vibrate more (temp increase)