Give two differences between emf and potential difference as applied to electric circuits.

State the factors on which the resistance of metallic conductor depends.

Given alongside is the circuit diagram in which three resistances $1 \mathrm{\Omega }, 2 \mathrm{\Omega }$ and $3 \mathrm{\Omega }$ are connected to a cell of emf $2 \mathrm{V}$ and internal resistance$0.5 \mathrm{\Omega }$.

(i) Calculate the total resistance of the circuit?

(ii) What is the reading of ammeter?

(iii) What will be the ammeter reading, if an exactly similar cell is connected in series with the given cell?

(iv) What will be the ammeter reading, if an exactly similar cell is connected in parallel with the given cell?

A battery of emf $7.5$ volts and internal resistance. $0.5 \mathrm{\Omega }$ is connected to a network of resistances, calculate

(i) external resistance

(ii) current through $8.0 \mathrm{\Omega }, 4.0 \mathrm{\Omega }$ and $2.2 \mathrm{\Omega }$ resistance.

(iii) terminal voltage of battery

Calculate effective resistance in figure $1, 2 \mathrm{and} 3$ across $\mathrm{AB}$.