1)(a) Explain the Forbe’s method for finding the thermal conductivity of good conductors.
(b) Compound bar of nickel and copper of equivalent cross section and equal length is so arranged that the free end of copper is in the steam chamber at 100°C and free end of nickel is in melting ice at 0°C. If there are no heat losses at sides, compute the temperature of the hot junction.
[Given: KCu = 390 W/m/K and KNi = 60W/m/K]
2) Describe the processes given below:
(a) Formation of ice on ponds.
(b) Thermal conduction in the compound medium when bodies are arranged in series.
3)(a) What do you mean by achromatism? Write down the condition for the achromatism of two thin lenses when they are in contact.
(b) Deduce the condition for achromatism of two thin lenses separated by the distance.
4) Describe the following with the help of appropriate diagrams:
(a) Longitudinal spherical aberration
(b) Lateral spherical aberration
5)(a) Write down the principle to be observed in acoustical design of the auditorium.
(b) Explain the method of measuring absorption coefficient of the material with essential theory.