(a) Explain briefly the purpose of earthing electrical appliance. (b) Why does the light frorr bulb connected to a simple cell dim and eventually goes off a...

(a) Explain briefly the purpose of earthing electrical appliance.

(b) Why does the light frorr bulb connected to a simple cell dim and eventually goes off after a while?

(c) A coil of incidence 0.007 H, a resistor of resistance 8 \(\Omega\) and a capacitor capacitance 0.001 F are connected in series an a.c. source of frequency \(\frac{500}{\pi}\)Hz. If the r.m.s voltages across the coil, the resistor and capacitor are 30v, 20v and 70v respectively;

(i) draw a vector diagram to illustrate the voltage across the components in the circuit.

(ii) Calculate the: (\(\alpha\)) r.m.s voltage of the source

(\(\beta\)) r.m.s current in the circuit;

(\(\gamma\)) power dissipated in the circuit.

iii) write down the sinusoidal equation for the r.m.s voltage, V, in terms of the time, t.