electrical energy and power

Question 1

What is electrical power defenition

Answer 1

rate of energy transfer by each electrical component

Question 2

What are 2 factors that power depends on

Answer 2

Current in component,

PD across it

Question 3

equation for electrical power and units for it

linking voltage

Answer 3

electrical power is measured in watts

electrical power = PD X Current

P = VI

Question 4

additional equations for power, HOW DO WE GET THEM

Answer 4

plug in v= IR

into P = VI

plug IR in once, OR rearrange V= IR for I and get V/R and plug into power eq.

Question 5

what other word can you use for energy transferred

Answer 5

work done

Question 6

How to derive p=vi

Answer 6

1. we know that power = work done /time
2. we know that PD = WORK DONE / CHARGE
   VQ = WORK DONE
3. So power = VQ/TIME
4. We know that Q= IT
5. Power = VIT / T
6. P = VI

Question 7

Equation for energy transferred

Answer 7

1. We know that P= VI
2. We know P = work done / time
3. work done/time = vi
4. VIT = W
5. W is energy transferred = work done

Question 8

define kilowatt hour

Answer 8

1000 watts for 3600s

so 3.6x10^6 J