Electricity is measured in kilowatt hours. An electric power meter is fixed in each and every house, industry to measure the amount of electricity consumed. The representative from the electricity board reads the meter at regular intervals and bills accordingly.
Electric power meter is a glass enclosure within which is a rotating metal disc. This disc rotates in proportion to the amount of electricity being used at that time. When many appliances are switched on, the disc rotates faster. When nothing is on, it does not rotate all. Each revolution represents a specific amount of electricity. There are gears inside the meter which are rotated by the disc. These gears cause the pointers on a dial move, showing the amount of electricity used.
The power meter is made up of five dials:
· The first dial on the right measures units and rotates clockwise.
· The next dial to the left measures tens and rotates counter-clockwise.
· The dial third to the left measures hundreds and rotates clockwise.
· The fourth dial to the left measures thousands and rotates counter-clockwise.
· The last dial on the left measures ten thousands and rotates clockwise.
Power meters are read from right to left and the numbers that the each arrow points to are noted down. If the arrow on a dial is in between two numbers, the lower number is recorded. The exception is if the pointer is between zero and nine, in which case nine is recorded because zero is always the beginning of the next revolution.
One kilowatt hour of electricity can supply enough energy to keep ten 100 watt bulbs burning for one hour.
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