<image 1>A transistor, which may be approximated as a hemispherical heat source of radius ro = 0.1 mm, is embedded in a large silicon substrate (k = 125 W/m$\cdot$  K) and dissipates heat at a rate q. All boundaries of the silicon are maintained at an ambient temperature of T$\infty$= 27C,except for the top surface, which is well insulated.evaluate the surface temperature of the heat source for q =4 W.
['340.93K', '350.93K', '360.93K']