Question

One junction of a certain thermoelectric couple is at a fixed temperature r T and the other junction is at temperature T . The thermo electromotive force for this is expressed by `E=K(T-T_(r ))[T_(0)-(1)/(2)(T+T_(r ))]`. At temperature `T=(1)/(2)T_(0)`, the thermoelectric power is
A. `1/2kT_(0)`
B. `kT_(0)`
C. `1/2kT_(0)^(2)`
D. `1/2k(T_(0)-T_(r))^(2)`

Answer 1

a) Thermoelectric power,
`S=(dE)/(dT) = d/(dT)[kT-T_(r).{T_(0) - 1/2(T+T_(r)}]`
Specific latent heat of vaporisatioin
`= (22.68 xx 10^(5)`J/kg= `X xx 10^(-3) xx 22.68 xx 10^(5)` ltrbgt `=Y xx 10^(-3) xx 3.36 xx 10^(5) + Y xx 10^(-3) xx 4200 xx 100)`
`therefore` `X/Y = (7.56)/(22.68) = 1/3`
`S=k(T-T_(r) xx (-1/2) + [T_(0) - 1/2(T_(0)/2 + T_(r))} xx k`
When `T=T_(0)/2`
`S= -k/2(T_(0)/2-T_(r)) + {T_(0)-1/2(T_(0)/2+T_(r))} xx k`
`=(-kT_(0))/4 + (kT_(r))/2 + kT_(0)-(kT_(0))/4 - (kT_(r))/2 = 1/2 kT_(0)`