A- your electrical bill last month was 790 kwh for 30 days of power. if coal was the only source of electricity for your house, how much coal (burned with 30% efficiency) does 790 kwh equate to? if you used the same amount of electricity each month of the year, how much coal is required? b- a typical day at university uses the same amount of electricity as that of 7,000 homes. how many joules are required to power one day at university? how much coal, burnt at 30% efficiency, does this equate to?