How is the resistance of wire affected if its length is doubled?
(a) Resistance of a wire is directly proportional to the length of a wire; so if the length is doubled, resistance is also doubled. (b) Resistance of a wire is inversely proportional to the area of cross-section the wire. Thus, if radius is doubled, area increases four times and hence the resistance becomes one-fourth.
How does resistance change with length of wire?
The resistance of a long wire is greater than the resistance of a short wire because electrons collide with more ions as they pass through. The relationship between resistance and wire length is proportional . The relationship between resistance and the area of the cross section of a wire is inversely proportional .
On what factors the resistance of a conductor depends give the mathematical expression?
On what factor the resistance of conductor depends give its mathematical. the resistance depends upon resistivity of the material, length, temperature, and area of cross-section. Mathematically, R=pl/A where p is the resistivity,l is the length and A is area of cross section. from above, p = RA/l = ohm*m2/m = ohm-metre …
What is the effect of temperature on the resistance of a conductor?
METALLIC CONDUCTOR When we increases the temperature the amplitude of vibration of atoms increases as result of which the number of collision among the electrons and atom increases, and hence resistances increases.
Does temperature affect resistance of a wire?
Heating a metal conductor makes it more difficult for electricity to flow through it. These collisions cause resistance and generate heat. Heating the metal conductor causes atoms to vibrate more, which in turn makes it more difficult for the electrons to flow, increasing resistance.
What is the formula of temperature coefficient of resistance?
The temperature coefficient of resistance for a resistor is determined by measuring the resistances values over an appropriate temperature range. The TCR is calculated as the average slope of the resistance value over this interval. This is accurate for linear relations, since the TCR is constant at every temperature.
What is the unit of temperature coefficient of resistance?
The resistance-change factor per degree Celsius of temperature change is called the temperature coefficient of resistance. This factor is represented by the Greek lower-case letter “alpha” (α). A positive coefficient for a material means that its resistance increases with an increase in temperature.