1) An electric immersion heater normally takes 97.0 min to bring cold water in a well‐insulated container to a certain temperature, after which a thermostat switches the heater off. One day the line voltage is reduced by 8.00% because of a laboratory overload. How long does heating the water now take? Assume that the resistance of the heating element does not change.

2) A capacitor with an initial potential difference of 110 V is discharged through a resistor when a switch between them is closed at t = 0 s. At t = 10.0 s, the potential difference across the capacitor is 1.65 V.

(a) What is the time constant of the circuit?

(b) What is the potential difference across the capacitor at t = 15.4 s?