an electric current of 3 Ampere flowing through an electric heating element of resistance R=20~ohms is embedded in 100g of oil calculate the specific heat capacity of the oil by 10°c in ten second.?

mhizzlee

6 years ago

Heat energy = Elect. energy


heat energy= I2RT

= 2 X 2 X 50 X 200

= 40000J

to convert to kJ, divide J by 1000

hence, 400001000 = 40kJ

Robert01

6 years ago

Let I= current= 3A
R= resistance= 20Ω
m= mass= 100g= (100/1000)kg= 0.1kg
c= specific heat capacity of the oil
Ø1= initial temperature= 0°C= (0 + 273)K= 273K
Ø2= final temperature= 10°C= (10 + 273)K= 283K
∆Ø= (Ø2 - Ø1)= 283K - 273K= 10K
t= 10s
H= heat energy= I²Rt

Recall,
Specific Heat Capacity(SHC), c= H/(mƯ)
c= I²Rt/(m∆Ø)

From the numerator,
I²Rt= (3)²(20)(10)
= 9 × 200
= 1800
= 1800 Joules(J)

And the denominator,
(mƯ)= (0.1)(10)
= (1/10) × 10
= 1
= 1kilogrammes Kelvin(kg K)

Thus, c= H/(m∆Ø) = I²Rt/(m∆Ø)= 1800/1= 1800
= 1800 J/kg·¹K·¹

Therefore, the Specific Heat Capacity(SHC) of the oil is 1800 Joules per kilogrammes per Kelvin temperature.

Thank you.