Question

A lamp has a power of 120 w and is left on for 24 hours. A television has a power of 350 W and is left on for 3 hours. Which statement correctly compares the energy used by these devices?
A. The television uses 3,780,000 J less than the lamp.
B. The television uses 6,588,000 J less than the lamp.
C. The revision uses 3,356,000 J more than the lamp.
D. The television uses 10,368,000 J more than the lamp.

Answer 1

Answer:

The answer is B

Explanation:

Because all of the other answer are not correct in this situation

Answer 2

Hello!

The answer is C. The television uses 6,588,000 J less than the lamp.

Why?

First, we must know that 1 Wh( Watt consumed in 1 hour) = 3600 J

Wh is the unit that express the energy amount of consumed in 60 minutes/ 1 hour.

So,

From the enunciate information we can calculate the energy consumed by the lamp and the television.

For the lamp, we have that it left on for 24 hours and it has a power of 120

For the television, we have that it left on for 3 hours and it has a power of 350W

Calculating the energy consumed (Wh) we have:

$Wh= Watt*Time= 120 Watt* 24 hours= 2880 Wh$

and converting it to Joule, we have:

$2880 Wh*\frac{3600 J}{1 Wh}= 10,368,000 J$

Doing the same for the television, we have:

$Wh= 350 Watt* 3 hours= 1050 Wh$

and converting it to Joule, we have:

$1050 Wh*\frac{3600 J}{1 Wh}= 3,780,000 J$

Finally, we have

$10,368,000J(Lamp)-3,780,000J(Television)= 6,588,000J$:

Then having calculated both consume, we have that the television uses 6,588,000 J less than the lamp.