# Homework Help: Unit 4 Edexcel Specimen Paper

1. May 14, 2012

### jsmith613

1. The problem statement, all variables and given/known data

Please can someone look at the attached quesiton (I have extracted MS and relevant previous pieces of information)

Where do they get the idea that 100 W is produced over 24 hours ??

2. Relevant equations

3. The attempt at a solution

I know power = work done / time
but if power is in Watts, time is in seconds (W = J/s)

also if each low energy bulb is 11W (11*4 = 44W). so surely no energy is needed from national grid but they suggest it does (44W << 100W)

please can someone explain the MS (or Q or both) to me

#### Attached Files:

• ###### EdSpec.jpg
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2. May 14, 2012

### flatmaster

He's saying the turbine would continuously produce 100 W over a 24 hour day while the demand for lightbulb is not continuous. He wanted to do his calculation in Watts instead of Jewels. If you prefer, you could calculate the total number of jewels produced over 24 hours and compare that to the total number of jewels consumed over 24 hours.

3. May 15, 2012

### jsmith613

but 11 W is less than 100W so why would energy be needed from national grid