Heat is conducted through a uniform tapered rod of cross section and l...
1. Rate of Heat Conduction:
To determine the rate of heat conduction, we need to use Fourier's Law of Heat Conduction, which states that the rate of heat conduction through a material is proportional to the temperature gradient across the material.
The formula for heat conduction is given by:
Q = k * A * (ΔT / L)
Where:
Q is the rate of heat conduction,
k is the thermal conductivity of the material,
A is the cross-sectional area of the rod,
ΔT is the temperature difference across the rod,
L is the length of the rod.
Given:
Length of the rod (L) = 50 cm
Temperature at the left end (T1) = 60 °C
Temperature at the right end (T2) = 150 °C
Cross-sectional area at the left end (A1) = 3 cm^2
Cross-sectional area at the right end (A2) = 8 cm^2
Thermal conductivity of the rod (k) = 60 W/m°C
Cross-sectional area at the point 30 cm from the hot end (A) can be calculated using similar triangles:
A = A1 + (A2 - A1) * (30 cm / 50 cm)
A = 3 cm^2 + (8 cm^2 - 3 cm^2) * (30 cm / 50 cm)
A = 4.6 cm^2
Temperature difference across the rod (ΔT) is given by:
ΔT = T2 - T1
ΔT = 150 °C - 60 °C
ΔT = 90 °C
Substituting the values into the formula, we get:
Q = 60 W/m°C * 0.046 m^2 * (90 °C / 0.5 m)
Q = 552 W
Therefore, the rate of heat conduction through the rod is 552 W.
2. Temperature at the Point 30 cm from the Hot End:
To determine the temperature at a specific point along the rod, we can use the equation for heat conduction and rearrange it to solve for ΔT.
The formula for temperature difference (ΔT) is given by:
ΔT = Q * L / (k * A)
Given:
Rate of heat conduction (Q) = 552 W
Length of the rod (L) = 50 cm
Thermal conductivity of the rod (k) = 60 W/m°C
Cross-sectional area at the point 30 cm from the hot end (A) = 4.6 cm^2
Substituting the values into the formula, we get:
ΔT = 552 W * 0.5 m / (60 W/m°C * 0.046 m^2)
ΔT = 95 °C
Since the temperature at the hot end (T1) is 60 °C, we can calculate the temperature at the point 30 cm from the hot end (T) as follows:
T = T1 + ΔT
T = 60 °C + 95 °C
T = 155 °C
Therefore, the temperature at the point 30 cm from the hot end is 155 °C.