science homework question!! plz help?

Question

Calculate the power of a kettel that works at 240v and draws a current of 10a. If its on for 20mins (1/3 of hour) then calculate the energy used in kwhrs and joules

Answer 1

Hello...
recall to formula of Power
P = V I
where V is Potential difference and I is the current ..
so P = 240 x 10 = 2400 W .......

in second part we have to find the energy consumed
Energy consumed = Power x time
Power = 2400 W = 2.4 KW and time = 1/3 hour

so , energy consumed = 2.4 * 1/3 = 0.8 KWH ..

to convert in joules ..use the relation
1 Kwh = 3.6 x 10^6 joules ..
0.8kwh = 0.8 x 3.6 x 10^ 6 joules
= 2.88 x 10^6 joules

hope this will help you .:)