A conical cavity of base diameter 15 cm and height 20 cm has inside su...
Q = E 1 A 1 σ b T 14 [1 – F 11/1 – (1 – E 1) F 11]. Here, F 11 = 0.649 and A 1 = 0.0503 m2.
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A conical cavity of base diameter 15 cm and height 20 cm has inside su...
Given data:
- Base diameter of conical cavity = 15 cm
- Height of conical cavity = 20 cm
- Inside surface temperature = 650 K
- Emissivity of each surface = 0.85
Calculating the net radiative heat transfer:
1. Surface Area of the Conical Cavity:
- The slant height of the conical cavity can be calculated using the Pythagorean theorem:
Slant height (l) = √(r^2 + h^2), where r is the base radius and h is the height.
Given r = 15/2 = 7.5 cm and h = 20 cm, we get l = √(7.5^2 + 20^2) ≈ 21.54 cm
- The surface area of the conical cavity can be calculated as:
A = πrl, where r is the base radius and l is the slant height.
A = π * 7.5 * 21.54 ≈ 404.68 cm^2
2. Radiative Heat Transfer:
- The radiative heat transfer can be calculated using the formula:
Q = ε * σ * A * (T^4 - T_s^4), where ε is the emissivity, σ is the Stefan-Boltzmann constant,
A is the surface area, T is the temperature of the cavity, and T_s is the surroundings temperature.
Given ε = 0.85, σ = 5.67 x 10^-8 W/m^2K^4, T = 650 K, and T_s = 0 K (assuming surroundings is a perfect blackbody), we can calculate Q.
3. Calculating the Net Radiative Heat Transfer:
- Substituting the values in the formula, we get:
Q = 0.85 * 5.67 x 10^-8 * 404.68 * (650^4 - 0^4)
Q ≈ 168.3 W
Therefore, the net radiative heat transfer from the conical cavity is approximately 168.3 W. Hence, the correct answer is option 'A'.