IB Physics SL C 3 5 Superposition Topic Practice

This question is in two parts. Part 1 is about a thermistor circuit. Part 2 is about vibrations and waves.
Part 1 Thermistor circuit
The circuit shows a negative temperature coefficient (NTC) thermistor X and a $100 \mathrm{k} \Omega$ fixed resistor R connected across a battery.

The battery has an electromotive force (emf) of 12.0 V and negligible internal resistance.

A second loudspeaker S emits the same frequency as L but vibrates out of phase with L . The graph below shows the variation with time t of the displacement x of the waves emitted by S and L .

On the graph, sketch the variation with t of x for the wave formed by the superposition of the two waves. be marked.