(Note: This exercise falls primarily in the realm of "developing numerical 
sense," in the context of the terrestrial application of electrical energy.)

We measure the power of light bulbs and electrical appliances using
a unit called a "watt."  A watt is in fact one joule per second.  So, for
example, a 60-watt light bult requires 60 joules of electrical energy each
second in order to stay lit.

(a) Using reasonable estimates, calculate how many joules of energy you use
each day to light your home.

(b) Using further reasonable estimates, calculate how many joules of energy
are used in the United States each day to light all the homes and businesses
throughout the country.

(c) Remember that the atomic bomb detonated over Hiroshima released 
approximately 1.8 * 10^13 joules of energy.  How does the amount of energy
you calculated in Part (b) compare to the detonation of that bomb?