Question

find out how the brightness is increased or decreased in a bulb by increasing the number of cells. Try out the activity with 1.5V, 5V and 12 Vand note down your obsetvation​

Answer 1

Brightness depends upon power dissipated by the bulb

P=VI

Voltage : V

Current : I I=V/R

P=V²/R

Hence as voltage increase the brightness increase

Order will be 12V>5V>1.5V

Answer 2

1.5 V < 5 V < 12 V.

• The increase or decrease in the brightness of the bulb doesn't only depend on the number of cells but depends on their arrangement.
• Placing cells in series increases the voltage in the circuit, in turn increasing the power dissipated by the bulb.
• Increase in the power dissipation increases the brightness.
• When the cells are arranged in parallel, the voltage gets divided for every cell connected, hence there will be a decrease in the power dissipated by the bulb.
• The decrease in power dissipation decreases brightness.