Question

?

Answer 1

efficiency is 1.7% so the actual output power is only 1.7% of 60

power = 1.7% of 60 = energy/time, solve for energy, make sure to convert everything to SI units

Answer 2

1.02

Answer 3

make sure you are solving for energy not just power

Answer 4

um i divide

Answer 5

power = 1.02 W = energy/time

solve for energy

Answer 6

time would be converted into seconds right?

Answer 7

yes

Answer 8

705.9

Answer 9

3600 seconds in an hour

power = 1.02 = energy/(12*3600)

energy = ?

Answer 10

44064

Answer 11

good

just going to ask @sillybilly123 if they can confirm something for me - when we're calculating energy used do we take 60W as the power or (1.7 % of 60W) I'm not 100% sure on the actual physics here

Answer 12

ok

Answer 13

I think it's actually just 60W since this represents the actual energy used and 1.7% of the 60W is the non-heat ouput (so light)

so I would actually re-do the calculations as

power = 60W = energy/time for 2,592,000 J as the total energy (?)

Answer 14

anyway, for ii) the CFL bulb, they want light so we will only take 8.5% of 18W as the power
so 1.53 W = your answer for ii)

Answer 15

for iii) heat energy = total energy - light energy

so (100% - 1.7%) of the total power gets converted to heat

(100% - 1.7%) * 60W = 58.98W

and then 58.98 = energy/time

solve for energy, where time = 12 hours

Answer 16

\(\color{#0cbb34}{\text{Originally Posted by}}\) @Vocaloid
I think it's actually just 60W since this represents the actual energy used and 1.7% of the 60W is the non-heat ouput (so light)

so I would actually re-do the calculations as

power = 60W = energy/time for 2,592,000 J as the total energy (?)
\(\color{#0cbb34}{\text{End of Quote}}\)

Answer 17

this for i

Answer 18

yes

Answer 19

and that's it for i right?

Answer 20

yes.

Answer 21

732.5

Answer 22

for iii

Answer 23

\(\color{#0cbb34}{\text{Originally Posted by}}\) @Vocaloid
for iii) heat energy = total energy - light energy

so (100% - 1.7%) of the total power gets converted to heat

(100% - 1.7%) * 60W = 58.98W

and then 58.98 = energy/time

solve for energy, where time = 12 hours
\(\color{#0cbb34}{\text{End of Quote}}\)


check your calculations again

Answer 24

58.98=e/43200

Answer 25

good, keep going

Answer 26

2546640

Answer 27

good, so 2546640J of heat

Answer 28

thank you so much