Electrical Sources And Internal Resistance

Question 1

What’s the definition of e.m.f. ?

Answer 1

The energy given to each coulomb of charge that passes through the supply

Question 2

What is t.p.d. ?

Answer 2

Terminal Potential difference is the voltage across the supply when current is flowing through it

Question 3

What does it mean for a circuit to be short circuited?

Answer 3

It means the external resistance is no longer part of the circuit so the current will increase ( you can find this by using the equation E = Ir)

Question 4

How do you find the emf of a circuit using a graph?

Answer 4

Find the value of the y-intercept (when current is 0)

Question 5

How do you find the internal resistance of a circuit using a graph?

Answer 5

• -m = Ir (find the negative of the gradient)
• use the equation E=Ir where E is the y-intercept and I is the x-intercept