The electrical energy supplied by a source is given by:

1. W = QV
2. W = VIt
3. W = I²Rt
4. All of the above

The S.I. unit of electrical power is :

1. volt x ampere
2. volt/ampere
3. joule x second
4. none of the above

1 kWh is equal to:

1. 3600 J
2. 3.6 x 10⁵ J
3. 3.6 x 10⁶ J
4. 3.6 x 10⁴ J