The circuit contains a battery with e.m.f. 9.0 V, a switch, resistor P, an ammeter, a 4.0 Ω resistor and a voltmeter. Fig. 6.1 gives the circuit diagram. Resistor P is a cylinder of length l, formed from conducting modelling clay. Fig. 6.2 displays resistor P. P has a resistance of 8.0 Ω. The conducting modelling clay from resistor P is then remoulded to produce a second cylindrical resistor with the same volume as resistor P but with a length $\frac{l}{2}$. Fig. 6.3 displays the remoulded resistor.
(a)[2]
State the relationship described by Ohm’s law.
(b(i))[2]
When the switch in Fig. 6.1 is closed, Calculate the ammeter reading.
(b(ii))[2]
Calculate the electrical power transferred to resistor P.
(c(i))[2]
Calculate the resistance of the resistor after reshaping.
(c(ii))[2]
The reshaped resistor is put into the circuit in place of resistor P. Calculate the new voltmeter reading. Show your working.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Potential difference across a component varies directly with current through it” …