(1) A battery of e.m.f. 15V and internal resistance 2 ohm is connected to two resistors of resistance 4 ohm and 6 ohm joined in series. Find the electrical energy spent per minute in 6 ohm resistor?
(2) Water in an electric kettle connected to a 220V supply took 5 minutes to reach its boiling point. How long would it have taken if the supply voltage had fallen to 200V?
(3) You have three resistors of values 2 ohm, 3 ohm and 5 ohm. How will you join them so that the total resitance is less than 1 ohm? Draw a diagram and find the total resistance.