Physics-
General
Easy
Question
Five rods of same dimensions are arranged as shown in the figure. They have thermal conductivities K1, K2, K3, K4 and K5. When points A and B are maintained at different temperatures, no heat flows through the central rod if

The correct answer is: 
For no current flow between C and D
Þ 
Þ
...(i)
Also
Þ
Þ
...(ii)
It is given that
hence from equation (i) and (ii) we get
Þ 
Related Questions to study
physics-
One end of a copper rod of length
and area of cross-section
is immersed in boiling water and the other end in ice. If the coefficient of thermal conductivity of copper is 92 cal/m-s-oC and the latent heat of ice is
, then the amount of ice which will melt in one minute is
One end of a copper rod of length
and area of cross-section
is immersed in boiling water and the other end in ice. If the coefficient of thermal conductivity of copper is 92 cal/m-s-oC and the latent heat of ice is
, then the amount of ice which will melt in one minute is
physics-General
physics-
Three rods of same dimensions are arranged as shown in figure they have thermal conductivities
and
The points P and Q are maintained at different temperatures for the heat to flow at the same rate along PRQ and PQ then which of the following option is correct

Three rods of same dimensions are arranged as shown in figure they have thermal conductivities
and
The points P and Q are maintained at different temperatures for the heat to flow at the same rate along PRQ and PQ then which of the following option is correct

physics-General
physics-
Three rods of the same dimension have thermal conductivities 3K, 2K and K. They are arranged as shown in fig. Given below, with their ends at 100oC, 50oC and 20oC. The temperature of their junction is

Three rods of the same dimension have thermal conductivities 3K, 2K and K. They are arranged as shown in fig. Given below, with their ends at 100oC, 50oC and 20oC. The temperature of their junction is

physics-General
physics-
The only possibility of heat flow in a thermos flask is through its cork which is 75 cm2 in area and 5 cm thick. Its thermal conductivity is 0.0075 cal/cm secoC. The outside temperature is 40oC and latent heat of ice is 80 cal g–1. Time taken by 500 g of ice at 0oC in the flask to melt into water at 0oC is

The only possibility of heat flow in a thermos flask is through its cork which is 75 cm2 in area and 5 cm thick. Its thermal conductivity is 0.0075 cal/cm secoC. The outside temperature is 40oC and latent heat of ice is 80 cal g–1. Time taken by 500 g of ice at 0oC in the flask to melt into water at 0oC is

physics-General
physics-
A composite metal bar of uniform section is made up of length 25 cm of copper, 10 cm of nickel and 15 cm of aluminium. Each part being in perfect thermal contact with the adjoining part. The copper end of the composite rod is maintained at
and the aluminium end at
. The whole rod is covered with belt so that there is no heat loss occurs at the sides. If
and
, then what will be the temperatures of
and
junctions respectively

A composite metal bar of uniform section is made up of length 25 cm of copper, 10 cm of nickel and 15 cm of aluminium. Each part being in perfect thermal contact with the adjoining part. The copper end of the composite rod is maintained at
and the aluminium end at
. The whole rod is covered with belt so that there is no heat loss occurs at the sides. If
and
, then what will be the temperatures of
and
junctions respectively

physics-General
physics-
Three rods made of the same material and having the same cross section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at
and
respectively. The temperature of the junction of the three rods will be

Three rods made of the same material and having the same cross section have been joined as shown in the figure. Each rod is of the same length. The left and right ends are kept at
and
respectively. The temperature of the junction of the three rods will be

physics-General
physics-
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 temperature. The ratio of the heat transferred through a cross-section of a semi-circular rod to the heat transferred through a cross section of the straight rod in a given time is

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 temperature. The ratio of the heat transferred through a cross-section of a semi-circular rod to the heat transferred through a cross section of the straight rod in a given time is

physics-General
physics-
The figure shows a glass tube (linear co-efficient of expansion is a) completely filled with a liquid of volume expansion co-efficient g. On heating length of the liquid column does not change. Choose the correct relation between g and a

The figure shows a glass tube (linear co-efficient of expansion is a) completely filled with a liquid of volume expansion co-efficient g. On heating length of the liquid column does not change. Choose the correct relation between g and a

physics-General
physics-
Two holes of unequal diameters d1 and d2
are cut in a metal sheet. If the sheet is heated

Two holes of unequal diameters d1 and d2
are cut in a metal sheet. If the sheet is heated

physics-General
Maths-
Factorize 
Factorize 
Maths-General
physics-
Out of the following, in which vessel will the temperature of the solution be higher after the salt is completely dissolved.

Out of the following, in which vessel will the temperature of the solution be higher after the salt is completely dissolved.

physics-General
physics-
Two substances A and B of equal mass m are heated at uniform rate of 6 cal s–1 under similar conditions. A graph between temperature and time is shown in figure. Ratio of heat absorbed
by them for complete fusion is

Two substances A and B of equal mass m are heated at uniform rate of 6 cal s–1 under similar conditions. A graph between temperature and time is shown in figure. Ratio of heat absorbed
by them for complete fusion is

physics-General
physics-
Which of the substances A, B or C has the highest specific heat ? The temperature vs time graph is shown

Which of the substances A, B or C has the highest specific heat ? The temperature vs time graph is shown

physics-General
physics-
The graph signifies

The graph signifies

physics-General
physics-
A student takes 50gm wax (specific heat = 0.6 kcal/kg°C) and heats it till it boils. The graph between temperature and time is as follows. Heat supplied to the wax per minute and boiling point are respectively

A student takes 50gm wax (specific heat = 0.6 kcal/kg°C) and heats it till it boils. The graph between temperature and time is as follows. Heat supplied to the wax per minute and boiling point are respectively

physics-General