Question

which will offer higher resistance 50w-220v or a 25w-220v lamp?? calculate the ratio of resistances​

Answer 1

Answer:

The Ratio of Resistances is 1:2.

Explanation:

Let the 2 bulbs be denoted as Bulb 1 and Bulb 2.

In Bulb 1,

Power = 50W

Potential = 220V

In Bulb 2,

Power = 25W

Potential = 220V

Current in Bulb 1 = Power = Potential*Current

= 50 = 220*I

= 0.22 A

Current in Bulb 2 = Power = Potential*Current

= 25 = 220*I

= 0.11 A

Resistance in Bulb 1 = Potential/Current

= 220/0.22 ohms

= 1000 ohms

Resistance in Bulb 2 = Potential/Current

= 220/0.11 ohms

= 2000 ohms

Ratio of Resistances = Bulb 1/Bulb 2

= 1000/2000

= 1:2

Hope this helps.