The resistance of a bulb filament is 100 ohm at a temperature of 100 degrees centigrade . If it's temperature coefficient of resistance be 0.005 per degree centigrade , it's resistance will become 200 ohm at a temperature of
Answers
Rt= Ro(1+alpha t)
Hence, 100ohm= Ro(1+0.005 x 100)
therefore, Ro= 100/1.5
Now, 200= 100/1.5(1+0.005 x t2)
0.005 x t2= 2
t2= 400 degree centigrade
But by this formula, alpha=(R2-R1)/R1(t2-t1) we have
0.005=200-100/ 100(t2-100)
t2=300 degree centigrade
Answer:
a.) The resistance of the bulb becomes 200 ohm at a temperature of 300 degrees celsius.
Explanation:
R 100=100Ω ,
T1=100oC ,
R′=200Ω ,
α=0.005 per oC
Step 1: Resistance-temperature relationship
R=R0 (1+α(T2−T1))
where is the coefficient of resistance to temperature.
So, R′=R 100 (1+α(T2−T1)) .... (1)
Step 2: The final temperature
Putting R values in 100,
T1 ,
R′, we obtain in equation (1)
200=100(1+0.005(T2−100))
Or, T2−100=200
← T2=300 degrees celsius
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The resistance will become 200 ohms at a temperature of .
Step-by-step explanation:
Given:
The resistance of a bulb filament ohm.
Temperature
.
Temperature coefficient of resistance ∝ per.
To find:
Find the resistance will become 200 ohms at a temperature of.
Formula used:
∝
Solution:
By using ∝
Hence, the temperature is .
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