Question

Which has a higher resistance: a 50 W lamp bulb or a 25 W lamp bulb and how many times?

Answer 1

Power = Voltage×Current

Current = Voltage / Resistance

 

By eliminating current we get Power = (Voltage)2/ Resistance

 

since all lamp are rated to operate at same voltage 230 V, we can say from the above statements that power is inversly proportional to Resistance.

 

if R25 is the resistance of 25W lamp and R50 is resistance of 50W lamp, then ( R25 / R50 ) = (50/25) = 2;

 

hence R25 has high resistance and it is two times of R50




hope its helpful

Answer 2

P = V * I

I = V/R

So, P = V²/R

As V is constant

Hence P is inversely proportional to R

Let the resistance of 25W bulb be R1

And resistance of 50 W bulb be R2

So R1/R2=25/50

HENCE R1 HAS HIGHER RESISTANCE