A 600-W TV receiver is turned on for 4 h with
nobody watching it. If electricity costs 10 cents/kWh,
how much money is wasted?
So this is a problem that we have taken from the book Fundamentals Of Electrical Circuits By Alexander. But if you want to take a look at the problem yourself, then go to Chapter 1 question 1.39 of the book.
Since this is a problem we have taken from the Chapter 1 – Basic Concepts, it should be easy. But is that right? Well, let us see as we try to solve it, shall we?
So how do we go about solving this problem?
Well as we always do, we will first break the problem into small parts. By doing that, we will be in a better position to understand the problem in the first place. Right?
So, here is our breakdown of the problem.
The Problem Breakdown
So let us read out the problem once again, line by line. Alright?
Now the first line of the question reads – “A 600-W TV receiver is turned on for 4 h with nobody watching it.”
So what do we learn from that? It means that we have a TV which consumes electricity at 600 Watts Per Hour or 600 Watt/Hr. But we can also write this as 0.6 Kilo Watts Per Hour or 0.6KW/Hr, right? So that means:
P = 0.6 KW/Hour
Ok! So with that being clear, we will move on to our next part of the question which reads – “If electricity costs 10 cents/kWh, how much money is wasted?”
From this sentence, we now know that the cost of 1 KW of Power consumption for every hour is 10 cents.
Electricity Price = 10c/KW
So the question after that then becomes quite simple, isn’t it? It is just asking us to find out what will be the electricity bill for running that A 600-W TV receiver for 4 hours.
A 600-W TV receiver Electricity Cost In 4 Hours?
So solving this now becomes a simple equation:
Total Bill = Power Consumed By TV in 4 hours * Elec. Price
So then what is the total Power consumed by the TV in 4 hours? It is simple right? If the TV consumes 0.6KW in 1 hour, then the amount of Power it consumes in 4 hours is:
Power consumed in 4 hours = 0.6KW * 4 = 2.4KW
So it is now clear right? The TV has consumed 2.4KW in 4 hours. So then what will be the electricity price for this much of power?
Total Bill = 2.4KW * 10 cents => $0.24