CBSE Questions for Class 11 Engineering Physics Thermal Properties Of Matter Quiz 11 - MCQExams.com

A Centigrade and Fahrenheit thermometers are dipped in boiling water. The water temperature is lowered unit the Fahrenheit thermometre registers a temperature of $$140^o$$. The fall of temperature as registered by the Centigrade thermometre is :
  • $$80^o$$C
  • $$40^o$$C
  • $$50^o$$C
  • $$90^o$$C
A sample of gas expands from volume  $$V _ { 1 }$$  to  $$V _ { 2 } .$$  The amount of work done by the gas is greatest when the expansion is
  • adiabatic
  • isobaric
  • isothermal
  • Equal in all above cases
End $$A$$ of a copper rod is. maintained in steam chamber and other end is maintained at $$0^{\circ}C$$. Assume $$x = 0$$ at $$A$$. The $$T - x$$ graph for the rod in steady state is
  • None of these
Heat current is maximum in which of the following (rods are of identical dimension)
  • Copper
  • Copper steel
  • Steel Copper
  • Steel
An ideal gas is initially at $$  P_{l}, V_{1} $$ is expanded to $$  P_{2}, V_{2} $$ and then compressed adiabatically to the same volume $$  V_{l} $$ and pressure $$  P_{3} $$.If  W  is the net work done by the gas in complete process which of the
  • $$
    W>0 ; P_{3}>P_{1}
    $$
  • $$
    W<0 ; P_{3}>P_{1}
    $$
  • $$W<0;{P_3}$$
  • $$P_{2}>P_{1}$$;$$W<0$$
A small quantity, mass m, of water at a temperature $$\theta$$ in ($$^oC$$) is poured on to a large mass M of ice which is at its melting point. If c is the specific heat capacity of water and L the latent heat of fusion of ice, then the mass of ice melted is given by : 
  • $$\dfrac{ML}{mc\theta}$$
  • $$\dfrac{mc\theta}{ML}$$
  • $$\dfrac{Mc\theta}{L}$$
  • $$\dfrac{mc\theta}{L}$$
A fixed mass of gas is taken through a process $$A\rightarrow B\rightarrow C\rightarrow A$$. Here $$A\rightarrow B$$ is isobaric $$B\rightarrow C$$ is adiabatic and $$C\rightarrow A$$ is isothermal

The pressure at $$C$$ is given by $$(\gamma=1.5)$$
1537783_2b96fcb3f9304823a2a43b13944ecf50.PNG
  • $$\frac{10^5}{64}\,N/m^2$$
  • $$\frac{10^5}{32}\,N/m^2$$
  • zero
  • $${10}^5\,N/m^2$$
If $$C_p$$ and $$C_v$$ are molar specific heats of an ideal gas at constant pressure and volume respectively. If $$\gamma$$ is ratio of two specific heats and $$R$$ is universal gas constant then $$C_p$$ is equal to?
  • $$\dfrac{R\gamma}{\gamma -1}$$
  • $$\gamma R$$
  • $$\dfrac{1+\gamma}{1-\gamma}$$
  • $$\dfrac{R}{\gamma -1}$$
$$2$$ mole ideal He gas and $$3$$ mole ideal $$H_2$$ gas at constant volume find out $$C_v$$ of mixture 
  • $$\dfrac{21 R}{10}$$
  • $$\dfrac{11 R}{10}$$
  • $$\dfrac{21 R}{5}$$
  • $$\dfrac{11 R}{5}$$
What happens in the process of thermionic emission?
  • Complete molecules are emitted from the surface of a hot liquid
  • Single atoms are emitted from the surface of a hot liquid
  • Electrons are emitted from the surface of a hot metal
  • Protons are emitted from the surface of a hot metal
Two plastic cups are placed one inside the other. A small spacer keeps the two cups separated. How water is poured into the inner cup and a lid is put on top, as shown.
Which statement is correct?
1647116_be477fdc0eee44f5a9eb9cdfda1e62a9.png
  • The bench is heated by conduction from the bottom of the outer cups
  • The lid reduced the energy gain by convection
  • There is no thermal conduction through the sides of either cup
  • Thermal radiation is prevented by the small air gap
r.m.s. speed of ideal gas at $$127^oC$$ is $$200m/s$$, the r.m.s. speed of same ideal gas at temperature $$227^oC$$ is:
  • $$100\sqrt{5}$$
  • $$200\sqrt{5}$$
  • $$100\sqrt{15}$$
  • $$100\sqrt{10}$$
Two moles of an ideal gas with $$\dfrac{C_P}{C_V}=\dfrac{5}{3}$$ are mixed with $$3$$ moles of another ideal gas with $$\dfrac{C_P}{C_V}=\dfrac{4}{3}$$. The value of $$\dfrac{C_P}{C_V}$$ for the mixture is :
  • $$1.47$$
  • $$1.45$$
  • $$1.42$$
  • $$1.50$$
Pressure of an ideal gas is increased by keeping temperature constant. The kinetic energy of molecules.
  • Decreases
  • Increases
  • Remains same
  • Increases or decreases depending on the nature of gas
In which of the following phenomena do heat waves travel along a straight line with the speed of light ? 
  • Thermal conduction
  • Thermal convection
  • Thermal radiation
  • Both, thermal conduction and radiation
Water does not freeze at the bottom of the lakes in winter because :
  • ice is a good conductor of hear
  • ice reflects heat and light
  • of anomalous expansion of water between $$4^oC$$ to $$0^oC$$
  • nothing can be said
Let $$C_v$$ and $$C_p$$ denote the molar heat capacities of an ideal gas at constant volume and constant pressure respectively.Which of the following is a universal constant?
  • $$ \dfrac{C_p}{C_v} $$
  • $$ C_p C_v $$
  • $$ C_p - C_v $$
  • $$ C_p + C_v $$
A steel scale gives correct reading at $$t_1 ^oC$$. When temperature changes to $$t_2 ^oC$$, then :
  • if $$t_2> t_1$$, reading is greater that true value
  • if $$t_2> t_1$$, reading is lesser that true value
  • the reading is always equal to true value
  • the reading is always less than true value
A physicist says "a body contains $$10\ joule$$ heat" but a physics learner says "this statement is correct only when the body is in liquid state". Mark correct option or options :
  • physicist statement is correct
  • physics learner's statement is correct
  • both statements are correct
  • both statements are wrong
A metal rod of length $$L$$ and cross-sectional area $$A$$ converts a large tank of water at temperature $$\theta_{0}$$ and a small vessel containing mass $$m$$ of water at initial temperature of $$\theta_{1}(< \theta_{0})$$. If the thermal conductivity of rod is $$K$$, then the time taken for the temperature of water in smaller vessel to become $$\theta_{2}(\theta_{1} < \theta_{2} < \theta_{0})$$ is:
(Given : Specific heat capacity of water is $$s$$ and all other heat capacities are neglected).
  • $$T = \dfrac {ms}{KA} \log \dfrac {(\theta_{0} - \theta_{1})}{(\theta_{0} - \theta_{2})}$$
  • $$T = \dfrac {Lms}{KA}\log \left (\dfrac {\theta_{0} - \theta_{1}}{\theta_{0} - \theta_{2}}\right )$$
  • $$T = \dfrac {2mLs}{KA} \left (\log \dfrac {(\theta_{0} - \theta_{1})}{\theta_{0} - \theta_{2}}\right )$$
  • None of the above
The quantity $$\dfrac{PV}{kT}$$ represents
  • mass of the gas
  • kinetic energy of the gas
  • number of moles of the gas
  • number of molecules in the gas
The temperature of a body is increased from $$27^oC$$ to $$127^oC$$. The radiation emitted by it increases by a factor of : 
  • $$(256/81)$$
  • $$(15/9)$$
  • $$(4/3)$$
  • $$(12/27)$$
Three rods of identical cross-sectional area and made from the same material form the sides of an equilateral triangle. The point $$A$$ and $$B$$ are maintained at $$T$$ and $$2T$$ respectively. In steady state temperature of point $$C$$ is $$T_c$$. ( Assuming only heat conduction takes place.) The value of $$T_c$$ is 

1738956_aeb7500b7e0c473ba5ddfb72f5a842c8.png
  • $$T/2$$
  • $$T$$
  • $$\dfrac{2}{3}T$$
  • $$\dfrac{3}{2}T$$
The net rate of heat loss by a hot body depends upon:
  • temperature of body
  • temperature of surroundings
  • material of body
  • nature of the surface
Three rods of the same cross-sectional and made of the same material from the sides of a triangle $$ABC$$ as shown. The points $$A$$ and $$B$$ are maintained at temperature $$T$$ and $$\sqrt 2 T$$ respectively in the steady state. Assuming that only heat conduction takes plane, the temperature at point $$C$$ is:
1738730_77328c07ee1f494796e5d3cdb357c55d.png
  • $$\left[\dfrac {2\sqrt 2 +\sqrt 3}{2+\sqrt 3}\right]T$$
  • $$\left[\dfrac {3 }{1+\sqrt 2}\right]T$$
  • $$\left[\dfrac {2}{\sqrt 3}\right]T$$
  • $$\left[\dfrac {\sqrt 5}{2}\right]T$$
Three identical rods of same material are joined to from an equilateral triangle. The temperature of end $$A$$ and $$B$$ is maintained constant as $$\sqrt {3}T$$ and $$T$$. The ratio of $$T_C / T_B$$ will be: (Assuming no loss of heat from surfaces) 
  • $$\dfrac {1+\sqrt 3}{2}$$
  • $$\dfrac {1+\sqrt 3}{2}$$
  • $$\dfrac {1+\sqrt 2}{2}$$
  • $$\dfrac {1-\sqrt 2}{2}$$
The temperature of end $$A$$ of a rod us maintained at $$0^oC$$. The temperature of end $$B$$ is changing slowly such that the rod may be considered in steady state at all time and is given by $$T_B $$ = $$\alpha T$$ ; where $$\alpha$$ is positive constant and $$t$$ is time. Temperature of point $$C$$, at a distance $$x$$ from end $$A$$, at any time is ____.
1738942_bbcedd571cd3476f82680987e2672811.png
  • $$\dfrac{\alpha xt}{L}$$
  • $$\dfrac{\alpha xt^2}{2L}$$
  • $$\dfrac{\alpha x^2t}{2L}$$
  • $$\dfrac{\alpha (L-x)}{L}t$$
If for hydrogen $$ C_{p}-C_{v}=m $$ and for nitrogen $$ C_{p}-C_{v}= $$ $$ n, $$ where $$ C_{p} $$ and $$ C_{v} $$ refer to specific heats per unit mass respectively at constant pressure and constant volume, the relation between $$ m $$ and $$ n $$ is (molecular weight of hydrogen $$ =2 $$ and molecular weight of nitrogen $$ =14 $$ )
  • $$n=14m$$
  • $$n=7m$$
  • $$m=7n$$
  • $$m=14n$$
An ideal gas undergoes the cyclic process shown in a graph below
1749708_4824e05c68504739b89d3f2e43ddc19a.PNG
  • $$T_1 = T_2$$
  • $$ T_1 > T_2$$
  • $$V_aV_c = V_bV_d$$
  • $$V_aV_b = V_cV_d$$

An immersion heater, in an insulated vessel of negligible heat capacity, brings 100 g of water to the boiling point from $$16^{0}C$$ in 7 min. Then

         The heat of vaporization of alcohol is
  • $$854 J/kg$$
  • $$ 854 \times 10^{3} J/kg$$
  • $$204 cal/g$$
  • $$204 cal/kg$$
Consider two rods of same length and different specific heats ($$s_1$$ and $$s_2$$), conductivities $$K_1$$ and $$K_2$$ and areas of cross section ($$A_1$$ and $$A_2$$) and both having temperature $$T_1$$ and $$T_2$$ at their ends. If the rate of heat loss due to conduction is equal, then
  • $$K_1 A_1$$ = $$K_2 A_2$$
  • $$K_2 A_1$$ = $$K_1 A_2$$
  • $$\dfrac{K_1 A_1}{s_1}$$ = $$\dfrac{K_2 A_2}{s_2}$$
  • $$\dfrac{K_2 A_1}{s_2}$$ = $$\dfrac{K_1 A_2}{s_1}$$
At temperature TK, the pressure of 4.0 g argon in a bulb is P. the bulb is put in a bath having temperature higher by 50 K than the first one. 0.8 g of argon gas had to be removed to maintained original pressure .The temperature T is equal to :
  • 510 K
  • 200 K
  • 100 K
  • 73 K
Heat is added to an ideal gas and the gas expands. In such a process the temperature: 
  • must always increase
  • will remain the same if the work done equals the hear added
  • must always decrease
  • will remain the same if change in internal energy equals the heat added
Three rods of identical cross-sectional area and made from the same metal form the sides of an isosceles triangle ABC right angles at B. The points A and B are maintained at temperatures T and $$\sqrt{2}T$$, respectively, in the steady state. Assuming that only heat conduction takes place, temperature of point C
1750218_32612211ae8e42829cf63a563b5fb4dd.PNG
  • $$ \frac {3T} {\sqrt{2} + 1}$$
  • $$ \frac {T} {\sqrt{2} + 1}$$
  • $$ \frac {3T} {3(\sqrt{2} - 1)}$$
  • $$ \frac {T} {\sqrt{2} - 1}$$
Write 'true' or 'false' for each statement:        
Medium is necessary for the transfer of heat by radiation.
  • True
  • False
A marble tile would feel cold as compared to a wooden tile on a winter morning, because the marble tile
  • is a better conductor of heat than the wooden tile.
  • is polished while wooden tile is not polished.
  • Reflects more heat than wooden tile.
  • is a poor conductor of heat than the wooden tile.
Write 'true' or 'false' for each statement:    
On touching a lump of ice, we feel cold because some heat passes from our body to the ice.
  • True
  • False
Choose the correct alternative:
In the process of convection, heat travels
  • sideways
  • downwards
  • upwards
  • in all direction
$$S.I.$$ unit of temperature is:
  • calorie
  • Joule
  • Celsius
  • Kelvin
Absolute scale of temperature is reproduced in the laboratory by making use of a
  • Radiation pyrometer
  • Platinum resistance thermometer
  • Constant volume helium gas thermometer
  • Constant pressure ideal gas thermometer
Wires A and B have identical lengths and have circular cross-sections. The radius of A is twice the radius of B i.e. $$r_A=2r_B$$. For a given temperature difference between the two ends, both wires conduct heat at the same rate. The relation between the thermal conductivities is given by :
  • $$K_A =4K_B$$
  • $$K_A =2K_B$$
  • $$K_A =K_B/2$$
  • $$K_A =K_B/4$$
The length of the two rods made up of the same metal and having the same area of the cross-section are $$0.6$$ m and $$0.8$$ m respectively. The temperature between the ends of the first rod is $$90 ^\circ C$$ and $$60 ^\circ C$$ and that for the other rod is $$150$$ and $$110 ^\circ C$$. For which rod the rate of conduction will be greater
  • First
  • Second
  • Same for both
  • None of the above
Calories is the unit of
  • Heat
  • Work
  • Temperature
  • Food
In cold countries, water pipes sometimes burst, because
  • Pipe contracts
  • Water expands on freezing
  • When water freezes, pressure increases
  • When water freezes, it takes heat from pipes
Absolute zero (0 K) is that temperature at which
  • Matter ceases to exist
  • Ice melts and water freezes
  • Volume and pressure of a gas becomes zero
  • None of these
Calorimeters are made of which of the following
  • Glass
  • Metal
  • Wood
  • Either (a) or (c)
Water is cooled from $$4^oC$$ to $$0^oC$$ it:
  • Contracts
  • Expands
  • First contrast, then expands
  • First expands then contrast
The velocity of heat radiation in vacuum is 
  • Equal to that of light
  • Less than that of light
  • Greater than that of light
  • Equal to that of sound
The coefficients of thermal conductivity of copper, mercury, and glass are respectively K, K, and K such that $$K > K > K$$. If the same quantity of heat is to flow per second per unit area of each and corresponding temperature gradients are X, X, and X, then 
  • $$X_c=X_m=X_g$$
  • $$X_c>X_m>X_g$$
  • $$X_c < X_m < X_g$$
  • $$X_m < X_c < X_g$$
Four rods of identical cross-sectional area and made from the same the metal form the sides of square. The temperature of two diagonally opposite points and $$T$$ and $$2T$$ respective in the steady-state. Assuming that only heat conduction takes place, what will be the temperature difference between the other two points 
  • $$\dfrac{\sqrt{2}+1}{2}T$$
  • $$\dfrac{2}{\sqrt{2}+1}T$$
  • $$0$$
  • None of these
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