1. | \(\theta_{1}=0, ~\theta_{2}=90\) |
2. | \(\theta_{1}=10,~\theta_{2}=85\) |
3. | \(\theta_{1}=20, ~\theta_{2}=80\) |
4. | \(\theta_{1}=30, ~\theta_{2}=100\) |
Two rods of identical dimensions are joined end-to-end, and the ends of the composite rod are kept at \(0^\circ\mathrm{ C}\) and \(100^\circ\mathrm{ C}\) (as shown in the diagram). The temperature of the joint is found to be \(40^\circ\mathrm{ C}.\) Assuming no loss of heat through the sides of the rods, the ratio of the conductivities of the rods \(K_1/K_2\) is:
1. \(\frac32\)
2. \(\frac23\)
3. \(\frac11\)
4. \(\frac{\sqrt3}{\sqrt2}\)
Two rods \(A\) and \(B\) of different materials are welded together as shown in the figure. Their thermal conductivities are \(K_1\) and \(K_2.\) The thermal conductivity of the composite rod will be:
1. | \(\frac{3(K_1+K_2)}{2}\) | 2. | \(K_1+K_2\) |
3. | \(2(K_1+K_2)\) | 4. | \(\frac{(K_1+K_2)}{2}\) |