Science : Ch 12 – Electricity

An ampere is the SI unit of electric current

Ammeter is a device used for measuring electric current in amperes

Three resistors of 2 Ω is required to get 6 Ω because resultant is more than individual so they all must be connected in series.

In parallel combination, the equivalent resistance is smaller than the least resistance used in the circuit.

The resistance of a bulb increases as the temperature of its filament increases

Ammeter at the times connected in series with in the circuit. The reading is independent from its location.

The resistivity does not change if the shape of resistor is changed because nature of material will remain same.

electrons move from low potential to high potential. Note: So, the end of high potential has more positive charges and the end of the battery with low potential has more negative charges. While the electric current flows from the high potential to the low potential.

Ohm's law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Therefore, if the voltage is increased, the current will increase provided the resistance of the circuit does not change.

one horse power is determined as almost 746 Watt in standard calculations. It derived its name from the following context: One horsepower is the amount of power used by a horse to lift a 550 pounds heavy object from a depth of 1 foot in one second. This power when converted to SI system gives 746 Watts.

A kilowatt-hour is an amount of energy consumed by a machine working at a steady rate of one kilowatt for one hour. As a result, Joule is a SI unit of energy, but Kilowatt-hour is a Commercial unit.