Science : Ch 12 – Electricity

Ammeter is a device used for measuring electric current in amperes

In parallel combination, voltage remains same across two points

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

In order to get the working of heater properly, fused wire of higher rating must be used.

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

The gap between conduction band and valence band is much greater than conductors which don't allow them to conduct electricity very easily which in result shows greater resistance, so insulators offer infinitely high resistance.

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.

Constant temperature makes the resistivity constant which made resistance constant. Constant resistance again made the Ohms law applicable. Thats why Ohms law is applied only at constant temperature. It is like the conditions apply of the law.