Two identical rods made of two different metals A and B with thermal conductivities K_ A and K_ B respectively are joined end to end. The free end of A is kept at a temperature T₁ while the free end of B is kept at a temperature T₂ ( < T ₁ ) . Therefore, in the steady state

Options

1. Athe temperature of the junction will be determined only by K_ A and K_ B .
2. Bif the lengths of the rods are doubled the rate of heat flow will be halved.
3. Cif the temperatures at the two free ends are interchanged the junction temperature will change.
4. Dthe composite rod has an equivalent thermal conductivity of 2 K_A K_B K_A+K_B .