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A stone of mass m is moved in a circle of radius r with constant speed υ. The work done by the force over half the circumference of the circle is
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The correct answer is:
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The energy distribution 
with the wavelength 
for the black body radiation at temperature 
is shown in the figure. As the temperature is increased the maxima will
The energy distribution with the wavelength for the black body radiation at temperature is shown in the figure. As the temperature is increased the maxima will
Physics-General
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The spectrum of a black body at two temperatures 27oC and 327oC is shown in the figure. Let A1 and A2 be the areas under the two curves respectively. The value of 
is
The spectrum of a black body at two temperatures 27oC and 327oC is shown in the figure. Let A1 and A2 be the areas under the two curves respectively. The value of is
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A body cools in a surrounding which is at a constant temperature of 
. Assume that it obeys Newton's law of cooling. Its temperature 
is plotted against time t. Tangents are drawn to the curve at the points 
and 
. These tangents meet the time axis at angles of 
and 
, as shown
A body cools in a surrounding which is at a constant temperature of . Assume that it obeys Newton's law of cooling. Its temperature is plotted against time t. Tangents are drawn to the curve at the points and . These tangents meet the time axis at angles of and , as shown
Physics-General
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Variation of radiant energy emitted by sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following option is the correct match
Variation of radiant energy emitted by sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following option is the correct match
Physics-General
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The adjoining diagram shows the spectral energy density distribution 
of a black body at two different temperatures. If the areas under the curves are in the ratio 16 : 1, the value of temperature T is
The adjoining diagram shows the spectral energy density distribution of a black body at two different temperatures. If the areas under the curves are in the ratio 16 : 1, the value of temperature T is
Physics-General
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The plots of intensity versus wavelength for three black bodies at temperatures T1, T2 and T3 respectively are as shown. Their temperature are such that
The plots of intensity versus wavelength for three black bodies at temperatures T1, T2 and T3 respectively are as shown. Their temperature are such that
Physics-General
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The graph. Shown in the adjacent diagram, represents the variation of temperature (T) of two bodies, x and y having same surface area, with time (t) due to the emission of radiation. Find the correct relation between the emissivity (e) and absorptivity (a) of the two bodies
The graph. Shown in the adjacent diagram, represents the variation of temperature (T) of two bodies, x and y having same surface area, with time (t) due to the emission of radiation. Find the correct relation between the emissivity (e) and absorptivity (a) of the two bodies
Physics-General
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The figure shows a system of two concentric spheres of radii r1 and r2 and kept at temperatures T1 and T2, respectively. The radial rate of flow of heat in a substance between the two concentric spheres is proportional to
The figure shows a system of two concentric spheres of radii r1 and r2 and kept at temperatures T1 and T2, respectively. The radial rate of flow of heat in a substance between the two concentric spheres is proportional to
Physics-General
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The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x, respectively are T2 and T1 (T2 > T1). The rate of heat transfer through the slab, in a steady state is 
, with ¦ which equal to
The temperature of the two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivity K and 2K and thickness x and 4x, respectively are T2 and T1 (T2 > T1). The rate of heat transfer through the slab, in a steady state is , with ¦ which equal to
Physics-General
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One end of a copper rod of uniform cross-section and of length 3.1 m is kept in contact with ice and the other end with water at 100°C. At what point along it's length should a temperature of 200°C be maintained so that in steady state, the mass of ice melting be equal to that of the steam produced in the same interval of time. Assume that the whole system is insulated from the surroundings. Latent heat of fusion of ice and vaporisation of water are 80 cal/gm and 540 cal/gm respectively
One end of a copper rod of uniform cross-section and of length 3.1 m is kept in contact with ice and the other end with water at 100°C. At what point along it's length should a temperature of 200°C be maintained so that in steady state, the mass of ice melting be equal to that of the steam produced in the same interval of time. Assume that the whole system is insulated from the surroundings. Latent heat of fusion of ice and vaporisation of water are 80 cal/gm and 540 cal/gm respectively
Physics-General
Physics-
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
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
Physics-General
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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
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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
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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/cmsecoC. 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/cmsecoC. 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
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