Define the ohm in electrical terms.
A cell X with electromotive force (e.m.f.) $1.5\ \text{V}$ and negligible internal resistance is linked in series with three resistors A, B and C, as shown in Fig. 6.1. Resistors A and B have resistances $6.0\ \Omega$ and $3.0\ \Omega$ respectively and are joined in parallel. Resistor C has resistance $4.0\ \Omega$ and is in series with the parallel arrangement. Calculate the current in the circuit.
Calculate the current through resistor B.
Calculate the ratio $\dfrac{\text{power dissipated in resistor B}}{\text{power dissipated in resistor C}}$.
The resistors A, B and C in (b) are wires made from the same material and having the same length. Explain how the resistors could be produced with different resistance values.
Calculate the ratio of the average drift speed of the charge carriers in resistor B to the average drift speed of the charge carriers in resistor C.
A cell with e.m.f. $1.5\ \text{V}$ and negligible internal resistance is connected in parallel with cell X in Fig. 6.1 with their positive terminals joined together. State the change, if any, in the current in cell X.
State the change, if any, in the current through resistor C.