Thermal Propert...

Two rods of same length and cross sections are joined end to end. Their thermal conductivities are in the ratio $$2 : 3$$. If the free end of the first rod is at $$0^{o}$$C and free end of the second rod is at $$100^{o}$$C , the temperature at the junction of the two rods after attaining steady state is:

Match List I and List II

List-I                                  List-II

a) P-V graph(T is constant)                            e) St. line cutting temp axis at - 273$$^{0}$$            

b) P-T graph(V is constant)                            f) Rectangular hyperbola

c) V-T graph(pressure P is constant)             g) A st.line parallel to axis

d) PV- P garph                                               h) St. line passing trhough origin (T is constant)

The thermal radiations are similar to :

If we place our hand below a lighted electric bulb. We feel warmer because of :

Two metal plates of same area and ratio of thickness $$1 : 2$$ and having ratio of thermal conductivities $$1 : 2$$ are in contact. If the free sides of the first plate is maintained at $$-20^{o}$$C and the free side of the other plate is maintained at $$+40^{o}$$C ,the temperature of the common surface after attaining steady state is:

Three rods made of same material and having the same cross section and lengths have been joined as shown in the figure. The temperature at the junction of the rods will be :

A double-pane window used for insulating a room thermally from outside consists of two glass sheets each of area 1m$$^{2}$$ and thickness 0.01m separated by 0.05m thick stagnant air space.In the steady state, the room-glass interface and the glass-outdoor interface are at constant temperatures of 270$$^{o}$$C and 0$$^{o}$$C respectively.The thermal conductivity of glass is 0.8 and of air 0.08Wm$$^{-1}$$K$$^{-1}$$.

The rate of flow of heat through the window pane is nearly equal to:

Two rods (one semi-circular and other straight) of same material and of same cross sectional area are joined as shown in the figure. The points $$A$$ and $$B$$ are maintained at different temperatures. The ratio of heat transferred through a cross-section of a semicircular rod to the heat transferred through a cross section of the straight rod in a given time is

Statement-1
Radiation involves transfer of heat by electromagnetic waves.
Statement-2
Electromagnetic waves do not required any material medium for propagation.

Three rods of same material and having same crosssection have been joined as shown in fig.Each rod is of same length. The left and right rods are kept at 0$$^{o}$$C and 90$$^{o}$$C respectively.The temperature of the junction of the three rods will be