4.2.4a Resistance

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Question 3

State, in terms of their structure, why metals are good conductors of electricity.

[1]

A cylindrical metal wire $W_1$ , of length $l$ and cross-sectional area $A$ , has a resistance of $Ω18\ \Omega$ . A second cylindrical wire $W_2$ having length $2 l$ and cross-sectional area $3 A$ , is made from the same metal.

Determine: (i) the resistance of $W_2$ .

[2]

(ii) the effective resistance of $W_1$ and $W_2$ when connected in parallel.

[2]

This parallel pair of wires is connected to a battery made from four identical cells in series, each of electromotive force (e.m.f.) $E$ . There is a current in each wire.

(i) State the e.m.f. of the battery in terms of $E$ .

[1]

(ii) The current in the battery is $IBI_{\text{B}}$ , the current in $W_1$ is $I_1$ , and the current in $W_2$ is $I_2$ . Rank these three currents in order from largest to smallest.

[2]

State, in terms of their structure, why metals are good conductors of electricity.

[1]

Determine: (i) the resistance of $W_2$ .

(ii) the effective resistance of $W_1$ and $W_2$ when connected in parallel.

[2]

This parallel pair of wires is connected to a battery made from four identical cells in series, each of electromotive force (e.m.f.) $E$ . There is a current in each wire.

(i) State the e.m.f. of the battery in terms of $E$ .

[1]

(ii) The current in the battery is $IBI_{\text{B}}$ , the current in $W_1$ is $I_1$ , and the current in $W_2$ is $I_2$ . Rank these three currents in order from largest to smallest.

[2]

4.2.4a Resistance

Question 3

Markscheme

4.2.4a Resistance

Question 3

Markscheme

4.2.4a Resistance

Question 3

4.2.4a Resistance Questions

4.2.4a Resistance

Question 3

4.2.4a Resistance Questions