Jon is a scientist researching the heat value of coal. which heat measurement should he use?

calories , joules and calorific value.

Explanation:

All fuels that produces some amount of energy on burning in the presence of oxygen. This energy is measured in terms of calories , joules or calorific value.

1 calorific value is the amount of energy produced when one unit weight of coal is burnt in oxygen.  

The calorific value is expressed in terms of  joules per kilogram

1. (1.2kw)x(15/60hours) = .3kwh --> a

2. (5kw)x(90/60hours)x(8cents/kwh) = $0.60 --> d

3. microwave --> 1200 watts = (1.2kw)x(6/60hours) = .12kwh

coffee-maker --> 900 watts = (.9kw)x(10/60hours) = .15kwh

therefore, it requires more energy for the coffee-maker to do the same amount of work.

so the answer is a.

wha is what i will use to get my free points