A solar docking station is used to charge the battery of an autonomous robotic lawnmower. The display on the docking station shows the voltage and current readings as the lawnmower charges.
(i) State the equation linking voltage, current, and resistance.
(ii) Use the readings on the docking station display to calculate the resistance of the circuit used to charge the battery. Give the unit.
The battery of the robotic lawnmower takes 150 minutes150\text{ minutes}150 minutes to charge. The charging current is 1.25 A1.25\text{ A}1.25 A.
(i) State the equation linking charge, current, and time.
(ii) Calculate the charge transferred to the battery.
(iii) The cable connecting the docking station to the lawnmower is replaced with a much longer cable of the same thickness and material. Explain how this would affect the time taken for the battery to charge (assume the same total charge is transferred to the battery).
