SSC RSMSSB JE Mock Test 2024 Heat Transfer Conduction Heat Conduction Through Plane and Composite Walls
The overall heat transfer coefficient (U) for a composite wall of thicknesses x1, x2, x3 and of corresponding thermal conductivities k1, k2, k3 is given by equation
1
\(\frac{1}{U} = \frac{{{k_1}}}{{{x_1}}} + \frac{{{k_2}}}{{{x_2}}} + \frac{{{k_3}}}{{{x_3}}}\)
2
\(U = {k_1}{x_1} + {k_2}{x_2} + {k_3}{x_3}\)
3
\(\frac{1}{U} = \frac{{{x_1}}}{{{k_1}}} + \frac{{{x_2}}}{{{k_2}}} + \frac{{{x_3}}}{{{k_3}}}\)
4
\(\frac{1}{U} = \frac{{{x_1}}}{{{k_1}}} + \frac{{{x_2}}}{{{k_2}}} + \frac{{{k_3}}}{{{x_3}}}\)
5
Question Not Attempted