Three conductors of conductances `G_(1), G_(2) " and " G_(3)` are connected in series. Find their equivalent conductance.

Two conductors of conductnaces G_(1) and G_(2) are connected in series. They are connected in parallel to another conductor of conductance G_(3) . Determine their equivalent conductance.

Statement I: Two solid cylindrical rods of identical size and different thermal conductivity K_1 and K_2 are connected in series. Then the equivalent thermal conductivity of two rods system is less than that value of thermal conductivity of either rod. Statement II: For two cylindrical rods of identical size and different thermal conductivity K_1 and K_2 connected in series, the equivalent thermal conductivity K is given by (2)/(K)=(1)/(K_1)+(1)/(K_2)

Two conductors of resistance R_(1) (50 +- 2) ohm and R_(2) = (100 +- 4) ohm are connected in (a) series and (b) parallel. Find the equivalent resistance.

Three metal rods of same lenghs and same area of cross sections having conductivities 1,2,3, units are connected in series Then their effective conductivity will be .

Two identical metal wires of thermal conductivities K_(1) and K_(2) respectively are connected in series. The effective thermal conductivity of the combination is :

n conducting wires of same dimensions but having resistivities 1,2,3,….n are connected is series. The equivalent resistivity of the combination is

There are three groups G_(1), G_(2) and G_(3) in a College with 20, 40 and 60 students respectively. The average marks obtained by groups G_(1), G_(2) and G_(3) are 50%, 60% and 70% respectively. Find the average marks of the entire college?