1. Determine the cost of heating 3 gallons

of water (water weighs 8.33L per gallon

) at a room temperature of 22 degrees

Celsius to the boiling point of 100

degrees Celsius at the energy rating of

P10.00 per KWHR. The heater

efficiency is 80%

2. There are 10 lamps connected in series.

Each lamp has a resistance of 60 ohms

and draws 0.2 ampere. Determine the

supply voltage in the system if the total

resistance in feeders is 8 ohms.

3. The motor delivers 5 HP at an

efficiency of 85%, the dc supply

voltage at the terminals of the

motor is 220 volts

Determine the system overall

efficiency if the resistance for each

feeder line is 0.06 ohm