Physics WAEC / WASSCE 2021 Electricity and Magnetism
(a)(i) What is meant by the root-mean-square value of an alternating current? (ii) Define impedance of an alternating current circuit. (b) An electrical device rated 120 V, 60 W is opened on a 240 V, 50Hz mains supply. The circuit has a capacitor connected in series with ihe electrical device and the supply. Calculate the capacitance of the capacitor. [\pi=3.142]. (c)(i) Define the capacitance of a capacitor. (ii) The circuit diagram above illustrates two capacitors of capacitance C\(_1\) and C\(_2\) connected in series across a 2V source. (i)Obtain an expression for the total capacitance in terms of C\(_2\). 2 mm 5 n (ii) Calculate the potential difference across each capacitor.