Question

1- define kilowatt hour and convert it into joule 2- define electro volt and express it in joule.

Answer 1

1 kilo watt hour is the total electric energy consumed when an electric appliance of power 1 kilo - watt works for one hour.
1 kWh = 1000 Wh = ( 1000 W ) X (60 X 60 s) = 3.6 X 10⁶ J

1 electron volt (eV) is the S I unit of electrical potential energy. 1 eV is defined as the K.E. gained or lost by an electron in moving through a potential difference of 1 volt.
1 eV = 1.6 X 10^-19 J