Three sums of electrical power have been discussed in this video.
This is the second part of sum discussion .
Sum 1: A water heater has a rating of 4 KVA , 240 V.

a) What is the electrical energy consumed by it in:

i)KWhr and

ii) in Joul.

if it is used for 180 minutes.

b) Find the cost of electricity if the rate is

Rs. 7.00 per commercial unit.

+ Solution 1 - Close Solution 1 Sum 2: The water in an electric kettle took 5 minutes to reach its boiling point when it is connected to 220 v supply.

How long would it have taken if the supply voltage had fallen to 200 v. + Solution 2 - Close Solution 2 Sum 3: What is the resistance under normal working conditions of 240V electric lamp rated at 60 W ? If two such lamps are connected in series across a 240 mains supply, explain why each one appears less bright. + Solution 3 - Close Solution 3

a) What is the electrical energy consumed by it in:

i)KWhr and

ii) in Joul.

if it is used for 180 minutes.

b) Find the cost of electricity if the rate is

Rs. 7.00 per commercial unit.

+ Solution 1 - Close Solution 1 Sum 2: The water in an electric kettle took 5 minutes to reach its boiling point when it is connected to 220 v supply.

How long would it have taken if the supply voltage had fallen to 200 v. + Solution 2 - Close Solution 2 Sum 3: What is the resistance under normal working conditions of 240V electric lamp rated at 60 W ? If two such lamps are connected in series across a 240 mains supply, explain why each one appears less bright. + Solution 3 - Close Solution 3