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The radiative heat transfer rate per unit area (W/m2) between two plane parallel gray surfaces (emissivity = 0.9) maintained at 400 K and 300 K is (σ = Stefan Boltzmann constant = 5.67 × 10–8 W/m2K4)
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- 992
- 812
- 464
- 567
- 992
Correct Option: B
For plane surfaces
| = | A | + | - 1 | ||
| ε1 | ε2 | ||||
Here , ε1 = ε2 = 0.9
| = | A | + | - 1 | ||
| 0.9 | 0.9 | ||||
| = 8 ∥ .84 | ≈ 812 | |||
| m2 | m2 |
