Efficiency

Question 1

The more … a device is … Energy …

Answer 1

Efficient
Less
Energy

Question 2

Energy efficiency=

Answer 2

Total input energy

Question 3

Calculate the efficiency and amount wasted
TI - 2000j
Output - 790j

Answer 3

Efficiency - 0.395 (useful/total)

Wasted - 1,210 (total-output)

Question 4

Energy =

Answer 4

Power (w) X time (s)

Question 5

1 watt =

Answer 5

1 j/s

Question 6

I unit of electricity=

Answer 6

1kw X 1h

Question 7

If 2.5 kW kettle is used for 10 hours a month how much is one unit

Answer 7

Energy = 2.5 kW times by 10 hours that =25 kWh = 25 units and one unit = 15p and 25 = 375p which is £3.75

Question 8

Work out the energy used
Power (w) 250
Time (s) 20

Answer 8

5,000

Question 9

Power =

Answer 9

Energy/ time

Question 10

Time =

Answer 10

Energy/ power

Question 11

E
-
PxT

Answer 11

Cost of electricity

Question 12

W to kW

Answer 12

Divide by 1000

Question 13

600 w =

Answer 13

0.6 kW

Question 14

Everytime energy is transferred some of it is…

Answer 14

Wasted

Question 15

What happens to the energy that is not usefully transferred by the solar cells

Answer 15

Wasted