Electrical Circuits

Question 1

Kirchhoffs second law

Answer 1

States that in any circuit the sum of the electromotive force is equal to the sum of the potential difference in a closed loop. This is a result of the conservation of energy

Question 2

What does the term lost volts mean

Answer 2

The potential difference across the internal resistor in the battery or cell

Question 3

EMF equation

Answer 3

E=I(R+r)

Question 4

Potential dividers formula

Answer 4

V out = (R2/R1+R2) x V in
Where V in is the emf
And V out is the pd across R2

Question 5

Investigation of potential divider circuits

Answer 5

A thermistor or LDR can be used to vary the output of a potential divider circuit. When V out is across a thermistor, a greater pd will be provided when the temperature decreases, because this increases the resistance of the thermistor. These circuits can be investigated using water baths and lamps to stimulate different environments, with a voltmeter across the desired component to record the changes in V out as the environmental factors affecting the resistance of the component are varied.