1.  A lamp has a power of 60 watts. It gives out light at a rate of 6 watts.

         a)  What is the amount of energy supplied to the lamp each second in joules?

         b)  What is the amount of energy transferred usefully as light each second in joules?

         c)  What is the amount of energy wasted each second in joules?

         d)  What is the efficiency of the lamp?

    2.  The following diagram is about a radio.

         a)  What is the useful energy?

         b)  What is the wasted energy?

         c)  What is the efficiency of the radio?