A cell of e.m.f 12V and internal resistance 4Ω is connected to an external resistor of resistance 2Ω. Find the current flow.

In the diagram above, a 200 W bulb is lighted by a 240 V a.c mains supply. If 1kwh is sold at N40, the cost of keeping the bulb lighted for a day is?

In the diagram above, if the south-poles of two magnets strokes steel bar, the polarities at T and V will respectively be