The thermo e.m.f. of a thermocouple is 25μV/°C at room temperature. A galvanometer of 40ohm resistance, capable of detecting current as low as 10–5A, is connected with the thermocouple. The smallest temperature difference that can be detected by this system is
(a) 16°C
(b) 12°C
(c) 8°C
(d) 20°C.
