Batteries

Question 1

What is internal resistance?

Answer 1

-In batteries, chemical energy is used to make electrons move, as they move, they collide with atoms inside the battery, so they have resistance
-Typically less than 1 ohm

Question 2

What is load resistance/external resistance?

Answer 2

-The total resistance of all the components in the external circuit

Question 3

What is electromotive force?

Answer 3

-The total amount of work the battery does on each coulomb of charge, is measured in volts
-Isn’t a force

Question 4

What is the terminal P.D?

Answer 4

-The potential difference across the load resistance is the work done when one coulomb of charge flows through the load resistance
-If there was no internal resistance, the terminal P.D would be the same as the e.m.f, in real supplies, there always is energy lost overcoming internal resistance

Question 5

What are lost volts?

Answer 5

-The energy wasted per coulomb overcoming the internal resistance

Question 6

How is conservation of energy used in batteries?

Answer 6

-Energy per coulomb supplied = energy per coulomb used in load resistance + energy per coulomb wasted in internal resistance

Question 7

How is e.m.f calculated in series and parallel?

Answer 7

-Series: Can be added to calculate the total e.m.f, as charge goes through all of the cells so gains from each
-Parallel: The e.m.f is the same all around, as the charge only gains from the ones it goes through