P2: OHM'S LAW

Question 1

Ohm’s law

Answer 1

-the current flowing through a resistor is directly proportional to the voltage
-the current across a resistor is inversely proportional to the resistance

Question 2

Ohm’s law practical

Answer 2

-set up a circuit with a cell, an ammeter,a voltmeter, a resistor and a variabler resistor
-set the variable resistor to the lowest setting
-record the ammeter and voltmeter readings
-increase the setting on the variable resistor and record the new voltage and current readings repeat for at least 6 different resistance settings
-plot a graph of voltage against current to see if they are directly proportional

Question 3

2 examples of non-ohmic components

Answer 3

-filament bulbs
-diodes

Question 4

Why does ohm’s law not apply to filament bulbs?

Answer 4

as current increases the temp of the bulb increases which means that less current can flow per unit potential dfference and therefore current isn’t increasing at the same rate as the voltage

Question 5

Why does ohm’s law not apply to diodes?

Answer 5

current will only flow in one direction (diode has a very high resistance in the other direction)