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question_answer1)
A piece of metal weight 46 g in air, when it is immersed in the liquid of specific gravity 1.24 at \[27{}^\circ C\]it weighs 30 g. When the temperature of liquid is raised to \[42{}^\circ C\]the metal piece weight 30.5 g, specific gravity of the liquid at \[42{}^\circ C\] is 1.20, then the linear expansion of the metal will be
A)
\[3.316\times {{10}^{-5}}{{/}^{0}}C\] done
clear
B)
\[2.316\times {{10}^{-5}}{{/}^{0}}C\] done
clear
C)
\[4.316\times {{10}^{-5}}{{/}^{0}}C\] done
clear
D)
None of these done
clear
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question_answer2)
A student takes 50 g wax (specific heat\[=0.6\text{ }kcal/kg{}^\circ C\]) 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)
500 cal, \[50{}^\circ C\] done
clear
B)
1000 cal,\[100{}^\circ C\] done
clear
C)
1500 cal,\[200{}^\circ C\] done
clear
D)
1000 cal,\[200{}^\circ C\] done
clear
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question_answer3)
Hot water cools from \[60{}^\circ C\]to \[50{}^\circ C\]in the first 10 minutes and to \[42{}^\circ C\] in the next 10 minutes. The temperature of the surrounding is
A)
\[5{}^\circ C\] done
clear
B)
\[10{}^\circ C\] done
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C)
\[15{}^\circ C~~~~\] done
clear
D)
\[20{}^\circ C\] done
clear
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question_answer4)
Three rods of equal length / are joined to form an equilateral triangle PQR. 0 is the mid point of R PQ. Distance OR remains same for small change in temperature. Coefficient of linear expansion for PR and RQ is same i.e. \[{{\alpha }_{2}}\] but that for PQ is \[{{\alpha }_{1}}\].Then
A)
\[{{\alpha }_{2}}=3{{\alpha }_{1}}\] done
clear
B)
\[{{\alpha }_{2}}=4{{\alpha }_{1}}\] done
clear
C)
\[{{\alpha }_{1}}=3{{\alpha }_{2}}\] done
clear
D)
\[{{\alpha }_{1}}=4{{\alpha }_{2}}\] done
clear
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question_answer5)
A body cools in a surrounding which is at a constant temperature of\[{{\theta }_{0}}\]. Assume that it obeys Newton's law of cooling. Its temperature \[\theta \]is plotted against time \[t\]. Tangents are drawn to the curve at the points \[P(\theta ={{\theta }_{1}})\]and\[Q(\theta ={{\theta }_{2}})\]. These tangents meet the time axis at angles of \[{{\phi }_{2\,}}\] and \[{{\phi }_{1}}\], as shown
A)
\[\frac{\tan {{\phi }_{2}}}{\tan {{\theta }_{1}}}=\frac{{{\theta }_{1}}-{{\theta }_{0}}}{{{\theta }_{2}}-{{\theta }_{0}}}\] done
clear
B)
\[\frac{\tan {{\phi }_{2}}}{\tan {{\theta }_{1}}}=\frac{{{\theta }_{2}}-{{\theta }_{0}}}{{{\theta }_{1}}-{{\theta }_{0}}}\] done
clear
C)
\[\frac{\tan {{\phi }_{1}}}{\tan {{\theta }_{2}}}=\frac{{{\theta }_{1}}}{{{\theta }_{2}}}\] done
clear
D)
\[\frac{\tan {{\phi }_{1}}}{\tan {{\theta }_{2}}}=\frac{{{\theta }_{2}}}{{{\theta }_{1}}}\] done
clear
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question_answer6)
Three discs A, B and C having radii 2m, 4m, and 6m respectively are coated with carbon black on their other surfaces. The wavelengths corresponding to maximum intensity are 300 nm, 400 nm and 500 nm, respectively. The power radiated by them are \[{{Q}_{a,\,}}{{Q}_{b,}}\,and\,{{Q}_{c}}\] respectively,
A)
\[{{Q}_{a,\,}}\]is maximum done
clear
B)
\[{{Q}_{b,}}\]is maximum done
clear
C)
\[{{Q}_{c}}\]is maximum done
clear
D)
\[{{Q}_{a,\,}}={{Q}_{b,}}\,={{Q}_{c}}\] done
clear
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question_answer7)
A clock with a metal pendulum beating seconds keeps correct time at\[0{}^\circ C\]. If it loses 12.5 s a day at\[25{}^\circ C\], the coefficient of linear expansion of metal of pendulum is
A)
\[\frac{1}{86400}/k{}^\circ C\] done
clear
B)
\[\frac{1}{43200}/k{}^\circ C\] done
clear
C)
\[\frac{1}{14400}/k{}^\circ C\] done
clear
D)
\[\frac{1}{28800}/k{}^\circ C\] done
clear
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question_answer8)
The specific heat of a substance varies with temperature \[t({}^\circ Q)\]as \[c=0.20+0.14t+0.23{{t}^{2}}\](cal/g/ C) The heat required to raise the temperature of 2 g of substance from \[5{}^\circ C\]to \[15{}^\circ C\]will be
A)
24 cal done
clear
B)
56 cal done
clear
C)
82 cal done
clear
D)
100 cal done
clear
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question_answer9)
A vessel contains \[M\] grams of water at a certain temperature and water at certain other temperature is passed into it at a. constant. Rate of\[mg/s\]. The variation - of temperature of the & mixture with time is shown in figure. The values of \[m\] and ware, respectively (the heat exchanged after a long Time (sec) time is 800 cal)
A)
40 and 2 done
clear
B)
40 and 4 done
clear
C)
20 and 4 done
clear
D)
20 and 2 done
clear
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question_answer10)
Two plates identical in size, one of black and rough surface (\[{{B}_{1}}\]) and the other smooth and polished (\[{{A}_{2}}\]) are interconnected by a thin horizontal pipe with a mercury pellet at the centre. Two more plates \[{{A}_{1}}\] (identical to\[{{A}_{2}}\]) and\[{{B}_{2}}\] (identical to\[{{B}_{1}}\]) are heated to the same temperature and placed closed to the plates \[{{B}_{1}}\] and \[{{A}_{2}}\] as shown in figure. The mercury pellet
A)
moves to the right done
clear
B)
moves to the left done
clear
C)
remains stationary done
clear
D)
starts oscillating left and right done
clear
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question_answer11)
A sphere and a cube of same material and same volume are heated up to same temperature and allowed to cool in the same surroundings. The ratio of the amounts of radiations emitted in equa time intervals will be
A)
\[1:1\] done
clear
B)
\[\frac{4\pi }{3}:1\] done
clear
C)
\[{{\left( \frac{\pi }{6} \right)}^{1/3}}:1\] done
clear
D)
\[\frac{1}{2}{{\left( \frac{4\pi }{3} \right)}^{1/3}}:1\] done
clear
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question_answer12)
A body cools in 7 min from \[60{}^\circ C\]to\[40{}^\circ C\]. What will be its temperature after the next 7 min? The temperature of surroundings is\[10{}^\circ C\].
A)
\[28{}^\circ C\] done
clear
B)
\[25{}^\circ C\] done
clear
C)
\[30{}^\circ C\] done
clear
D)
\[22{}^\circ C\] done
clear
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question_answer13)
An incandescent lamp consuming \[P=54\text{ }W\]is immersed into a transparent calorimeter containing \[V={{10}^{3}}c{{m}^{3}}\]of water. In 420s the water is heated by\[4{}^\circ C\]. The percentage of the energy consumed by the lamp that passes out of the calorimeter in the form of radiant energy is
A)
81.5% done
clear
B)
26% done
clear
C)
40.5% done
clear
D)
51.5% done
clear
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question_answer14)
A vessel is partly filled with a liquid. Coefficients of cubical expansion of material of the vessel and liquid are \[{{\gamma }_{V}}\] and \[{{\gamma }_{L}}\] respectively. If the system is heated, then volume unoccupied by the liquid will necessarily
A)
remain unchanged if \[{{\gamma }_{V}}={{\gamma }_{L}}\] done
clear
B)
increase if \[{{\gamma }_{V}}={{\gamma }_{L}}\] done
clear
C)
decrease if \[{{\gamma }_{V}}={{\gamma }_{L}}\] done
clear
D)
none of the above done
clear
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question_answer15)
Assuming the sun to be a spherical body of radius\[R\] at a temperature of \[T\] kelvin, evaluate the total radiant power incident on the earth at a distance r from the sun.
A)
\[{{r}^{2}}_{0}{{R}^{2}}\sigma \frac{{{T}^{4}}}{4\pi {{r}^{2}}}\] done
clear
B)
\[{{R}^{2}}\frac{\sigma {{T}^{4}}}{{{r}^{2}}}\] done
clear
C)
\[4\pi {{r}^{2}}_{0}{{R}^{2}}\frac{\sigma {{T}^{4}}}{{{r}^{2}}}\] done
clear
D)
\[\pi r_{0}^{2}{{R}^{2}}\frac{\sigma {{T}^{4}}}{{{r}^{2}}}\] done
clear
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question_answer16)
An external pressure \[P\] is applied on a cube at \[0{}^\circ C\]so that it is equally compressed from all sides. K is the bulk modulus of the material of the cube and a is its coefficient of linear expansion. Suppose we want to bring the cube to its original size by heating. The temperature should be raised by
A)
\[\frac{3\alpha }{PK}\] done
clear
B)
\[3PK\alpha \] done
clear
C)
\[\frac{P}{3\alpha K}\] done
clear
D)
\[\frac{P}{\alpha K}\] done
clear
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question_answer17)
An electrically heated coil is immersed in a calorimeter containing 360 g of water at\[10{}^\circ C\]. The coil consumes energy at the rate of 90 W. The water equivalent of calorimeter and coil is 40 g. The temperature of water after 10 min is
A)
\[4.214{}^\circ C\] done
clear
B)
\[42.14{}^\circ C\] done
clear
C)
\[30{}^\circ C\] done
clear
D)
None of these done
clear
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question_answer18)
The wavelength of maximum energy released during an atomic explosion was \[2.93\times {{10}^{-10}}\] m. Given that Wien's constant is \[2.93\times {{10}^{-3}}\] m-K, the maximum temperature attained must be of the order of
A)
\[{{10}^{-7}}K\] done
clear
B)
\[{{10}^{7}}K\] done
clear
C)
\[{{10}^{-}}^{13}K\] done
clear
D)
\[5.86\times {{10}^{7}}K\] done
clear
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question_answer19)
A solid whose volume does not change with temperature floats in a liquid. For two different temperatures \[{{t}_{1}}\] and \[{{t}_{2}}\] of the liquid, fractions \[{{f}_{1}}\]and \[{{f}_{2}}\]of the volume of the solid remain submerged in the liquid. The coefficient of volume expansion of the liquid is equal to
A)
\[\frac{{{f}_{1}}-{{f}_{2}}}{{{f}_{2}}{{t}_{1}}-{{f}_{1}}{{t}_{2}}}\] done
clear
B)
\[\frac{{{f}_{1}}-{{f}_{2}}}{{{f}_{1}}{{t}_{1}}-{{f}_{2}}{{t}_{2}}}\] done
clear
C)
\[\frac{{{f}_{1}}+{{f}_{2}}}{{{f}_{2}}{{t}_{1}}-{{f}_{1}}{{t}_{2}}}\] done
clear
D)
\[\frac{{{f}_{1}}+{{f}_{2}}}{{{f}_{1}}{{t}_{1}}-{{f}_{1}}{{t}_{2}}}\] done
clear
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question_answer20)
A solid copper sphere (density \[\rho \] and specific heat capacity c) of radius \[r\] at an initial temperature 200 K is suspended inside a chamber whose walls are at almost 0 K. The time required (in \[\mu s\]) for the temperature of the sphere to drop to 100 K is
A)
\[\frac{72}{7}\frac{r\rho c}{\sigma }\] done
clear
B)
\[\frac{7}{72}\frac{r\rho c}{\sigma }\] done
clear
C)
\[\frac{27}{7}\frac{r\rho c}{\sigma }\] done
clear
D)
\[\frac{7}{27}\frac{r\rho c}{\sigma }\] done
clear
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question_answer21)
2 kg of ice at \[-20{}^\circ C\]is mixed with 5 kg of water at \[20{}^\circ C\]in an insulating vessel having a negligible heat capacity. Calculate the final mass of water (in kg) remaining in the container. It is given that the specific heats of water and ice are 1 kcal/kg per\[{}^\circ C\]and \[0.5\text{ }kcal/kg/{}^\circ C\]while the latent heat of fusion of ice is 80 kcal/kg.
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question_answer22)
The absolute coefficient of expansion of a liquid is 7 times that the volume coefficient of expansion of the vessel. Then the ratio of absolute and apparent expansion of the liquid is ________.
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question_answer23)
AIL glass flask contains some mercury. It is found that at different temperatures the volume of air inside the flask remains the same. What is the volume (in cc) of mercury in this flask if coefficient of linear expansion of glass is \[9\times {{10}^{-6}}/{}^\circ C\] while of volume expansion of mercury is \[1.8\times {{10}^{-4}}/{}^\circ C?\]
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question_answer24)
The coefficient of thermal conductivity of copper is nine times that of steel. In the composite cylindrical bar shown in figure, what will be the temperature (in\[{}^\circ C\]) at the junction of copper and steel?
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question_answer25)
The temperatures across two different slabs A and B are shown in the steady state (as shown in figure).The ratio of thermal conductivities of A and B is ______.
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