Explore BrainMass

# Relationship between Resistance and Temperature

Not what you're looking for? Search our solutions OR ask your own Custom question.

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

The current, passing through an incandescent light bulb, becomes lower than the initial value, some moments later after it is switched on. Why?
a) Change in drift velocity
b) Change in Electrostatic Potential (Potential drop across the conductor)
c) Change in Resistance
d) Change in Conductance
Give arguments in support of your answer. Also, explain the full phenomenon lying behind it.

https://brainmass.com/physics/temperature/relationship-between-resistance-temperature-260120

## SOLUTION This solution is FREE courtesy of BrainMass!

Problem: The current, passing through an incandescent light bulb, becomes lower than the initial value, some moments later after it is switched on. Why?

Solution:
The resistivity of a conductor increases with Temperature. An ideal electrical conductor (here, a filament of the electric bulb) has a positive temperature coefficient of resistance. So, when a current flows through the filament of an incandescent light bulb, its temperature increases (Thermal effect of current). So, its resistivity also increases with increase in temperature. Hence, the current that flows through an incandescent light bulb immediately after it is turned on is higher, since then the bulb is at a lower temperature and hence the resistance is also less. After a few moments, the temperature of the filament of the bulb rises, and hence resistance also increases and so the current becomes lower than the initial value.

OPTION - C
Here, one thing is to be noted. OPTION C and OPTION D are directly related. A change in resistance of a conductor directly affects the change in its conductance. In other words, Resistance is inversely proportional to conductance of a conductor. Hence an ideal electrical conductor has negative temperature coefficient of conductance. If temperature increases, conductance decreases.

Thank you for using Brainmass

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!