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A ring consisting of two parts ADB and ACB of same conductivity k carries an amount of heat H. The ADB part is now replaced with another metal keeping the temperatures T1 and T2 constant. The heat carried increases to 2H. What should be the conductivity of the new ADB part? Given 
The correct answer is:
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The wall with a cavity consists of two layers of brick separated by a layer of air. All three layers have the same thickness and the thermal conductivity of the brick is much greater than that of air. The left layer is at a higher temperature than the right layer and steady state condition exists. Which of the following graphs predicts correctly the variation of temperature T with distance d inside the cavity?
The wall with a cavity consists of two layers of brick separated by a layer of air. All three layers have the same thickness and the thermal conductivity of the brick is much greater than that of air. The left layer is at a higher temperature than the right layer and steady state condition exists. Which of the following graphs predicts correctly the variation of temperature T with distance d inside the cavity?
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Two sheets of thickness d and 2 d and same area are touching each other on their face. Temperature TA, TB, TC shown are in geometric progression with common ratio r = 2. Then ratio of thermal conductivity of thinner and thicker sheet are
Two sheets of thickness d and 2 d and same area are touching each other on their face. Temperature TA, TB, TC shown are in geometric progression with common ratio r = 2. Then ratio of thermal conductivity of thinner and thicker sheet are
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The spectral emissive power 
for a body at temperature T1 is plotted against the wavelength and area under the curve is found to be A. At a different temperature T2 the area is found to be 9A. Then 
The spectral emissive power for a body at temperature T1 is plotted against the wavelength and area under the curve is found to be A. At a different temperature T2 the area is found to be 9A. Then
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A cuboid ABCDEFGH is anisotropic with 
Coefficient of superficial expansion of faces can be
A cuboid ABCDEFGH is anisotropic with Coefficient of superficial expansion of faces can be
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An ice cube at temperature – 20°C is kept in a room at temperature 20°C. The variation of temperature of the body with time is given by
An ice cube at temperature – 20°C is kept in a room at temperature 20°C. The variation of temperature of the body with time is given by
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Heat is conducted across a composite block of two slabs of thickness d and 2d. Their thermal conductivities are 2k and k respectively. All the heat entering the face AB leaves from the face CD. The temperature in °C of the junction EF of the two slabs is :
Heat is conducted across a composite block of two slabs of thickness d and 2d. Their thermal conductivities are 2k and k respectively. All the heat entering the face AB leaves from the face CD. The temperature in °C of the junction EF of the two slabs is :
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A thermally insulated vessel contains some water at 00C. The vessel is connected to a vacuum pump to pump out water vapour. This results in some water getting frozen. It is given Latent heat of vaporization of water at 0°C =21 × 105 J/kg and latent heat of freezing of water = 3.36 × 105 J/kg. The maximum percentage amount of water that will be solidified in this manner will be
A thermally insulated vessel contains some water at 00C. The vessel is connected to a vacuum pump to pump out water vapour. This results in some water getting frozen. It is given Latent heat of vaporization of water at 0°C =21 × 105 J/kg and latent heat of freezing of water = 3.36 × 105 J/kg. The maximum percentage amount of water that will be solidified in this manner will be
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One end of a 2.35m long and 2.0cm radius aluminium rod (K = 235 W.m-1K-1) is held at 200C. The other end of the rod is in contact with a block of ice at its melting point. The rate in kg s-1 at which ice melts is
One end of a 2.35m long and 2.0cm radius aluminium rod (K = 235 W.m-1K-1) is held at 200C. The other end of the rod is in contact with a block of ice at its melting point. The rate in kg s-1 at which ice melts is
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A spherical ball of density r and radius 0.003m is dropped into a tube containing a viscous fluid filled up to the 0 cm mark as shown in the figure. Viscosity of the fluid = 1.260 N.m–2 and its density 
L= /2 = 1260 kg.m–3. Assume the ball reaches a terminal speed by the 10 cm mark. The time taken by the ball to traverse the distance between the 10 cm and 20 cm mark is
A spherical ball of density r and radius 0.003m is dropped into a tube containing a viscous fluid filled up to the 0 cm mark as shown in the figure. Viscosity of the fluid = 1.260 N.m–2 and its density L= /2 = 1260 kg.m–3. Assume the ball reaches a terminal speed by the 10 cm mark. The time taken by the ball to traverse the distance between the 10 cm and 20 cm mark is
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A cubical block of side ‘a’ and density ‘r’ slides over a fixed inclined plane with constant velocity ‘v’. There is a thin film of viscous fluid of thickness ‘t’ between the plane and the block. Then the coefficient of viscosity of the thin film will be:
A cubical block of side ‘a’ and density ‘r’ slides over a fixed inclined plane with constant velocity ‘v’. There is a thin film of viscous fluid of thickness ‘t’ between the plane and the block. Then the coefficient of viscosity of the thin film will be:
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Figure shows a siphon. Choose the wrong statement:
Figure shows a siphon. Choose the wrong statement:
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A liquid of mass 1 kg is filled in a flask as shown in figure. The force exerted by the flask on the liquid is (g = 10 m/s2):
A liquid of mass 1 kg is filled in a flask as shown in figure. The force exerted by the flask on the liquid is (g = 10 m/s2):
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Two drops of same radius are falling through air with steady velocity of v cm/s. If the two drops coalesce, what would be the terminal velocity?
Two drops of same radius are falling through air with steady velocity of v cm/s. If the two drops coalesce, what would be the terminal velocity?
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A large tank is filled with water (density = 103 kg/m3). A small hole is made at a depth 10 m below water surface. The range of water issuing out of the hole is Ron ground. What extra pressure must be applied on the water surface so that the range becomes 2R (take 1 atm = 105 Pa and g = 10 m/s2):
A large tank is filled with water (density = 103 kg/m3). A small hole is made at a depth 10 m below water surface. The range of water issuing out of the hole is Ron ground. What extra pressure must be applied on the water surface so that the range becomes 2R (take 1 atm = 105 Pa and g = 10 m/s2):
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In a cylindrical vessel containing liquid of density r, there are two holes in the side walls at heights of h1 and h2 respectively such that the range of efflux at the bottom of the vessel is same. The height of a hole, for which the range of efflux would be maximum, will be
In a cylindrical vessel containing liquid of density r, there are two holes in the side walls at heights of h1 and h2 respectively such that the range of efflux at the bottom of the vessel is same. The height of a hole, for which the range of efflux would be maximum, will be
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