Temperature of coefficient of given material of coil using potentiometer

1. Temperature coefficient of resistance of given
material of coil
MRS.P.KANMANI,
ASSISTANT PROFESSOR,
DEPARTMENT OF PHYSICS,
V.VANNIAPERUMAL COLLEGE FOR WOMEN,
VIRUDHUNAGAR.

2. Temperature coefficient of resistance of given material of
coil
Temperature Coefficient:
 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. Pure metals typically have positive temperature
coefficients of resistance.

3. Temperature coefficient of resistance of given material of
coil
Temperature Coefficient:
 A negative coefficient for a material means that its resistance decreases with an
increase in temperature. Semiconductor materials (carbon, silicon, germanium)
typically have negative temperature coefficients of resistance.

4. Temperature coefficient of resistance of given material of
coil
Aim :
To determine the temperature coefficient of resistance of given material of coil
Apparatus :
Coil for which temperature coefficient of resistance is to be determined, Carey
foster bridge resistance boxes, standard resistance
Formula:
𝛼 =
𝑥2 − 𝑥1
𝑥1 𝑡2 − 𝑥2 𝑡1
/ ∘𝐶

5. Temperature coefficient of resistance of given material of
coil
𝛼 =
𝑥2 − 𝑥1
𝑥1 𝑡2 − 𝑥2 𝑡1
/ ∘𝐶
𝛼----------- temperature coefficient of resistance of material of coil
𝑥1 --------- resistance of the coil at 𝑡1
∘𝐶
𝑥2 --------- resistance of the coil at 𝑡2
∘𝐶

6. Temperature coefficient of resistance of given material of
coil
Bt - Battery
HR - High Resistance
R - Variable resistance
K1, K2 - Key
Cr - Commutator
G - Galvanometer
X - Unknown resistance of coil of given material
Rh - Rheostat
DPDT - Double pole double throw switch
J - Jockey

7. Temperature coefficient of resistance of given material of
coil
R in ohm Balancing length
when R is included
𝑙1 in cm
Balancing length
when X is included
𝑙2 in cm
𝑋1 = 𝑅
𝑙2
𝑙1
in ohm Mean
To find 𝑋1 temperature = 0∘
𝐶
R in ohm Balancing length
when R is included
𝑙1 in cm
Balancing length
when X is included
𝑙2 in cm
𝑋2 = 𝑅
𝑙2
𝑙1
in ohm Mean
To find 𝑋2 temperature = 100∘
𝐶

8. Temperature coefficient of resistance of given material of
coil
Result:
Temperature coefficient of resistance of given material of coil = -----------