Circuit equations

Question 1

pd across the resistors in series with a cell

Answer 1

current x the resistance of each resistor

Question 2

Current through each resistors in parallel with a cell

Answer 2

pd across the parallel combination/resistor’s resistance

Question 3

cell current for multiple cells in series.

Answer 3

net emf/total resistance

Question 4

If cells in series are connected in the same direction

Answer 4

The net emf is the sum of the individual emfs

Question 5

If cells in series are connected in the opposite directions

Answer 5

The net emf is the difference between the emfs in each direction.

Question 6

For a circuit with n identical cells in parallel the current through each cell =

Answer 6

I/n, where I is the total current supplied by the cells

Question 7

For a circuit with n identical cells in parallel the lost pd in each cell =

Answer 7

Ir/n where r is the internal resistance of each cell.

Question 8

For a circuit with n identical cells in parallel the terminal pd across each cell =

Answer 8

V = ε - Ir/n

Question 9

Each time an electron passes through identical parallel cells:

Answer 9

It travels through one of the cells only as the cells are in parallel, therefore the cell acts as a source of emf and internal resistance r/n.

Question 10

For a diode circuit:

Answer 10

• A pd of .6 V exists across a diode that is forward biased and passing a current.
• A diode that is reverse-biased has infinite resistance.