railway RRB JE (CBT I + CBT II) Mock Test 2024 Heat Transfer Conduction Critical Thickness of Insulation
For given combined radiative and convective heat transfer coefficient ‘ht’ and given thermal conductivity k, Critical thickness of insulation for cylinder and sphere is given as
1
\(\frac{k}{{{h_t}}}\) and \(\frac{k}{{h_t^2}}\)
2
\(\frac{k}{{{h_t}}}\) and \(\frac{{2k}}{{{h_t}}}\)
3
\(\frac{{2k}}{{{h_t}}}\) and \(\frac{k}{{h_t^2}}\)
4
\(\frac{{2k}}{{{h_t}}}\) and \(\frac{k}{{{h_t}}}\)