The instant at which bulb is switched on, its power is maximum, then it decreases to a steady value.

This can be explained by the increasing resistance due to heating of the filament. (P = V*2*/R). My doubt in the above is in the steady value. Logically, I think as the resistance keeps increasing, the fractional change in it becomes small enough to say that resistance becomes constant, but how do I get to this value mathematically. I tried but could not solve it. My effort : enter image description here

I thought of getting a function of power and time in which at t = infinity, the constant value of power could be obtained. But I am inable to arrive there.Is there a mistake in the approach or the calculation? Please help.



Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.