A flint plate has thickness 5 cm, thermal conductivity 1 W/mK, convective heat transfer coefficients on its two flat faces of 10 W/m2 +K and 20 W/m2K. the overall heat transfer coefficient for such a flat plate is (IES-01)
(a) 5 W/m2K (b) 6.33 W/m2K
(c)20 W/m2K (d) 30 W/m2K