Heat
Kinetic Theory of Gases-Laws
Q.1 Two gasses X and
Y having the same temperature T, same
pressure p and same volume V are mixed. If the mixture is at the
same temperature T and occupies the
same volume V, the pressure of the
mixture is
(a) 2p
(b) p (c) p/2 (d) 4/p
Q.2 Two vessels
having equal volume contain molecular hydrogen at one atmosphere and helium at
two atmosphere respectively. If both samples are at the same temperature, the
rms speed of hydrogen molecules is
(a) equal to that of helium (b) twice that of helium
(c) half that of helium (d) Ö2 times that of helium
Q.3 The molecules of
a given mass of an ideal gas have rms speed of 300m/s at 37°C and 2 ´ 105
Pa. When the temperature is 967°C and the
pressure is 6´105Pa,
the rms value in m/s is
(a) 600Ö3 (b) 600Ö2 (c) 600
(d) 1200
Q.4 The rms speed of
the molecules of hydrogen at 27 °C is v1 and the rms speed of oxygen at 402°C is v2, then
(a) 3v1
= 8v2 (b) 8v1 =
3v2 (c) 9v1 =
4v2 (d) 4v1 =
9v2
Q.5 At identical
temperatures, the rms speed of hydrogen molecules is 4 times that for oxygen
molecules. In a mixture the two gases are present in the mass ratio of 1:8
respectively. The rms speed of all molecules of the mixture is n times the rms speed for oxygen
molecules, where n is
(a) 3 (b) 4/3 (c) (8/3)1/2 (d) (11)1/2
Q.6 At room
temperature the rms speed of the
molecules of a certain diatomic gas is found to be 1930m/s. The gas is
(a) H2 (b) F2 (c) O2 (d) C12
Q.7 Three closed
vessels A,B and C are at the same temperature and contain gases which obey
Maxwellian distribution of velocities. Vessels A contains only O2, B
only N2 and C a mixture of
equal quantities of O2 and N2. If the average speed
of O2 molecules in vessels A
is v1 that of the N2 molecules in vessel B is v2,
the average speed of the O2 molecules in vessel C is
(a) (v1
+ v2)1/2 (b) v1 (c) (v1 v2)1/2
(d) Ö3kT/M
where M is the mass of an oxygen molecule.
*Q.8 A mixture of two
gases A and B is in thermal equilibrium
(a) the rms speed of the molecules-A is
equal to the rms speed of the molecules-B.
(b) the average kinetic energy of
molecules-A is equal to the average kinetic energy of molecules-B.
(c) the heavier molecules move with
smaller rms speed but average kinetic energy of heavier molecules is same as
that of lighter molecules.
(d) the heavier molecules move with
smaller rms speed and they have a small average kinetic energy than those of
lighter molecules.
Q.9 The energy of a
gas per liter is 300J, then its pressure in N/m2 will be
(a) 3 ´ 105 (b) 6 ´ 105 (c) 105 (d) 2 ´ 105
Q.10 If the number of
molecules of H2 are double than that of O2, then ratio of
average kinetic energy of hydrogen and that of oxygen, both at 300 K is
(a) 1 : 1 (b) 1
: 2 (c) 2 : 1 (d) 1 : 16
Q.11 At what
temperature, the mean kinetic energy of O2 will be same for H2
molecules at- 73°C
(a) 127°C (b) 527°C (c) -73°C (d) -173°C
Q.12 The kinetic
energy of oxygen at-23°C and 60cm
pressure is 120J, when its volume is one liter. The kinetic energy of hydrogen
having volume one liter, temperature 227°C and pressure 120 cm will be
(a) 480J (b) 960J (c) 240J (d) 120J
Q.13 A box containing
N molecules of a perfect gas at
temperature T1 and
pressure p1. The number of
molecules in the box is doubled keeping the mean energy of the gas same as
before. If the new pressure is p2
and temperature T2, then
(a) p2 = p1,
T2 = T1 (b) p2 = p1,
T2 = T1/2 (c) p2 = 2p1, T2
= T1 (d) p2 = 2p1,
T2 = T1/2
Q.14 A box containing
N molecules of a perfect gas at
temperature T1 and
pressure p1. The number of
molecules in the box is doubled, keeping the total kinetic energy of the gas
same as before. If the new pressure is p2
and temperature T2, then
(a) p2 = p1, T2 = T1 (b) p2 = p1, T2
= T1/2
(c) p2 = 2p1,
T2 = T1 (d) p2 = 2p1, T2
= T1/2.
Q.15 An ideal gas is
found to obey an additional law Vp2 = constant. The gas is initially
at temperature T and volume V. When it expands to a volume 2V, the temperature
becomes
(a) TÖ2 (b) 2T (c) T/Ö2 (d) 4 T
Q.16 An ideal gas expands in such a manner
that its pressure and volume comply with the condition pV2 =
constant. During this process, the gas is
(a) heated (b) cooled
(c) neither heated not cooled (d) first heated and
then cooled.
Q.17 Two jars A and B contains Helium and
Oxygen at the same temperature and at pressure of 1 atm and 4 atm respectively.
If E1 and E2 be the average kinetic energy of translation
per per molecule of each gas then
(a) E1 = 8 E2 (b) E2 = 8 E1 (c) E1
= E2 (d) E1
= 4 E2
ANSWER SHEET ( Kinetic
Theory of Gases)
1.
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(a)
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2.
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(d)
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3.
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(c)
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4.
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(a)
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5
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(d)
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(a)
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(b)
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8.
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(b), (c)
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(d)
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(a)
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(c)
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(c)
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(c)
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(b)
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(a)
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(b)
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(c)
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Thermal Expansion
(Objective Question)
*Q.1 A hollow copper
cylinder is heated, then its
(a) internal
diameter decreases (b) external diameter increases
(c) volume of metal
increases (d) density of material decreases.
Q.2 Two rods of
different materials having co-efficient of thermal expansion a1, a2 and Young’s
modulii Y1, Y2 respectively are fixed between two rigid
massive walls. The rods are heated such that they undergo the same increase in
temperature. There is no bending of the rods. If a1 : a2 = 2 : 3, the
thermal stress developed in the two rods are equal provided Y1 : Y2 is equal to
(a) 2 : 3 (b) 1 : 1 (c) 3 : 2 (d) 4 : 9
*Q.3 A metallic
circular disc having a circular hole at its centre is rotating about an axis
passing through its centre and perpendicular to its plane. When the disc is
heated
(a) the speed of
disc increases (b) the diameter of hole decreases
(c) the moment of
inertia of disc increases (d) the
speed of disc decreases
Q.4 A crystal has a
co-efficient of liner expansion 12 ´ 10-7/°C in one
direction and 213 ´ 10-7/°C in every
direction at right angles to it. The co-efficient of cubical expansion of the
crystal is
(a)
36 ´ 10-7/°C (b) 639 ´ 10-7/°C
(c) 273 ´ 10-7/°C (d) 438 ´ 10-7/°C
Q.5 A metallic
hollow sphere of negligible co-efficient of cubic expansion just floats in
water at 4°C. If the water
is (i) heated to 6°C, (ii) cooled
to 2°C, then
(a)
sphere sinks in both cases (i) and (ii)
(b)
sphere floats in both cases (i) and (ii)
(c) sphere sinks in both case (i) but floats
in case (ii)
(d) sphere floats in both cases (i) but
sinks in case (ii)
Q.6 A metal ball
immersed in alcohol weighs W1 at 0°C and W2 at 59°C. The co-efficient of cubical expansion of the metal is less than
that of the alcohol. Assuming that the density of the metal is large compared
to that of alcohol, it can be shown that
(a) W1 > W2 (b) W1
= W2 (c) W1 < W2 (d) W2
= (W1/2)
Q.7 A block of wood
is floating on water at 0°C with certain
volume v above water. The temperature
of water is slowly raised from 0°C to 15°C, then the
volume v will
(a) remain unchanged (b) decrease
(c) first increase then decrease (d) first decrease then increase
Q.8 In the previous question,
the distance between the holes will
(a)
increase
(b)
decrease
(c) remain
constant
(c)
may either
increases or decrease depending on the positions of the holes on the sheet and
on the ratio d1/d2.
Q.9 A metal wire of length ò and area of cross-section A is fixed between rigid
supports at negligible tension. If this is cooled, the tension in the wire will
be
(a) proportional
to ò (b) inversely
proportional to ò
(c) independent
of ò (d) independent of A
Q.10 Two metal rods of the same
length and area of cross-section are fixed end to end between rigid supports.
The materials of the rods have Young modulii Y1 and Y2,
and coefficients of linear expansion a1 and a2. The junction between the rods does not shift if the
rods are cooled
(a) Y1a1 =Y2a2 (b) Y1a2 =Y2a1 (c) Y1a21 =Y2a22 (d) Y12a1 =Y22a2
Q.11 When the temperature of a body
increases from t to t +∆t,
its moment of inertia increases from I to
I + ∆I.
The coefficient of linear expansion of the body is a. The ratio ∆I/I
is equal to
(a) ∆t/t (b) 2∆t/t (c) a∆t (d) 2a∆t
Q.12 A horizontal tube, open at
both ends, contains a column of liquid. The length of this liquid column does
not change with temperature. Let g = coefficient of
volume expansion of the liquid and a = coefficient of
linear expansion of the martial of the tube
(a) g = a ( b) g = 2a
(c) g = 3a (d) g = 0
Q.13 A solid whose volume does not
change with temperature floats in a liquid. For two different temperature t1
and t2 of the liquid, frictions f1
and f2 of the volume of
the solid remain submerged in the liquid. The coefficient of volume expansion
of the liquid is equal to
(a) f1-f2 /f2t1-f1t2 (b) f1-f2/f1t1-f2t2 (c)
f1+f2/f2t1+f1t2 (d) f1+f2/f1t1+f2t2
Q.14 A solid with coefficient of
linear expansion a just floats in a liquid whose coefficient of volume
expansion is heated, the solid will
(a) sink
in all causes (b) continue to float in all cases
(c) sink
if g > 3a (d) sink if g < 3 a
Q.15 The
moment of inertia of a body is I and the linear coefficient of expansion is a. If the temperature rises by a
small amount Dq, then the change in the moment of inertia is
approximately
(a) a I (Dq) (b) 2 a I (Dq) (c) 4 a I (Dq) (d) a I (Dq)/2
*Q.16 A
bimetallic strip is formed out of two identical strips, one of copper and the
other of brass. The coefficients of linear expansion of two metals are ac and aB. On heating, the temperature of the strip goes up by DT and the strip bends to form an are of circle of radius R. Then R is
(a)
proportional to T (b) inversely
proportional to T
(b)
proportional to |
aA- aB | (d) inversely proportional to | aA- aC |
*Q.17 The
temperature of an isotropic cubical solid of length L, density d and
coefficient of linear expansion a per Kelvin is raised by 10°C, then at this temperature to a good approximation
(a)
length is L (1 + 10 a)
(b)
total surface area is L (1 + 2a)
(c)
density is d (1 + 30 a)
(d)
density is d/ (1 + 30 a)
Q.18 Two
rods of lengths l1 (aluminimum) and l2 (steel having thermal coefficient of linear expansion aA and as respectively are connected end-to-end. Change in temperature DT produces equal changes in their lengths. The ratio l1/(l1 + l2) is
(a) aA/ aS (b) aA/ (aA + aS)
(c) aS/ (aA + aS) (d) aS/ aA
ANSWER SHEET
Thermal Expansion
1.
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(b), (c), (d)
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(c)
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(c), (d)
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(d)
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(a)
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(c)
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(c)
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(a)
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(c)
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(d)
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(b)
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(a)
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(c)
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(b)
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16.
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(b), (d)
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17.
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(a), (d)
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18.
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(c)
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Thermal
Conduction & Radiation
Q.1 Two identical
vessels A and B having the same thickness of walls, but their thermal
conductivities are KA and KB. Both are filled with the
same quantity of ice. If the time taken for melting the ice fully is 20 s and
30 s respectively, then the ratio KA
and KB will be
(a) 4 : 9 (b) 2 : 3 (c) 3 : 2 (d) 9 : 4
Q.2 Two rods A and B are of equal lengths. Their ends are kept between the same
temperature and their area of cross – sections are A1 and A2
and thermal conductivities k1
and k2. The rate of heat
transmission in the two rods will be equal, if
(a) k1 A2 = k2 A1
(b) k1 A1 = k2 A2
(c) k1 = k2 (d) k1 A12 = k2
A22
Q.3 Wires A and B have identical lengths and have circular cross sections. The
radius of A is twice the radius of B i.e,RA = 2RB. 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
(a) kA
= 4kB (b) kA = 2kB (c) kA
= kB/2 (d) kA = kB/4
Q.4 Two identical
plates of different metals as joined to form a single plate whose thickness of
each plate. If the co-efficients of conductivity of each plate are 2 and 3
units respectively, then the conductivity of the composite plate will be
(a) 5 (b) 2.4 (c) 1.5 (d) 1.2
Q.5 A wall has two
layers A and B, each made of different materials. Both the layers have the same
thickness. The thermal conductivity of the material A is twice that of B.
Under thermal equilibrium, the temperature difference across the wall is 36°C. The
temperature difference across the layer A
is
(a) 6°C (b) 12°C (c) 8°C (d) 24°C
Q.6 A cylinder of
radius R made of a material of
thermal conductivity k1 is
surrounded by a cylindrical shell of inner radius R and outer radius 2R
made of a material of thermal conductivity k2.
The two ends of the combined system are maintained at two different
temperatures. There is no loss of heat across the cylindrical surface and the
system is in steady state. The effective thermal conductivity of the system is
(a) k1
+ k2 (b) k1 k2/ (k1 + k2) (c) k1 + 3k2) /4 (d) (3
k1 + k2) /4
Q.7 Two different
metallic rectangular blocks A and
have the same cross section and length. They are kept in contact with their
cross sections together. One end of block A
is at temperature 100°C while the far
end of blocks B is at 0°C. If the
condctivity co – efficient of A and B are in the ratio 1:3, the temperature
of the junction in the steady state is
(a) 25°C (b) 50°C (c) 75°C (d) 100°C
Q.8 The thermal
conductivity of a metal is 1600 W/m.K. In the steady state the temperature
gradient which will transmit 400´103 W/m2 of heat energy should be
(a) 100°C (b) 120°C (c) 250°C (d) 200°C
Q.9 A rod of length
0.5m is heated at one end. On the steady state the temperatures at the ends of
the rod are 100°C and 0°C. The
temperature at a point distance 10cm from the hot end will be
(a) 80°C (b) 60°C (c) 40°C (d) 20°C
Q.10 Four identical
rods each of length l and of the same
material are joined end-to-end to form a square. If the temperature difference
between the ends of a diagonal is 100°C, then the temperature difference between the ends of other
diagonal will be
(a) 0°C (b) 100/l°C (c) 100/2l°C (d) 100°C
Q.11 A sphere, a cube
and a thin circular plate made up of same material and having the same mass are
initially heated to a temperature of 200°C. Which of these objects will cool slowest, when left in air at
room temperature
(a) sphere (b) cube
(c) circular path (d) all will cool at the same rate
Q.12 A body at 300°C radiates 105J/m2.
If sun radiates 109W/m2, then its temperature is
(a) 3000°C (b) 5457°C (c) 300 ´ 104°C (d) 5730°C
Q.13 A bucket full of
water cools from 75°C to 70°C in time t1, from 70° to 65°C in time t2 and from 65° in 65°C in time t3, then
(a) t1 = t2 = t3 (b) t1 > t2 > t3 (c) t1 < t2
< t3 (d) t1 > t2
< t3
(a) E/A (b) E/A.T (c) EA (d) EA/T
Q.15 The ratio of
wavelengths of emissive corresponding to the maximum emission in the spectrum
of a black – body heated to temperature 1000K and 2000K respectively is
(a) ¼ (b) ½ (c) 2 (d) 4
Q.16 Two black –
bodies A and B emit radiations with peak intensities at wavelengths 400nm and
800nm respectively. If their temperatures are TA and TB
respectively in kelvin scale and their emissive powers are EA and EB
then
(a) TA/TB = 2
(b) EA/EB = 2 (c) EA/EB = 8 (d) EA/EB = 16
Q.17 If the
temperature of the sun becomes twice its present value, then radiated energy
would be predominantly in the
(a) ultraviolet
region (b) X – rays region
(c) Infra red region (d) Visible
region
Q.18 A solid sphere
and a hollow sphere of the same material having equal radii are at the same
temperature at the instant t = 0
(a) At t = 0, both will emit equal amount of
energy per second
(b) At t = 0, both will absorb equal amount of
energy from the surroundings
(c) At t = 0, the rate of cooling i.e., dT/dt will be the same
(d) At t > 0, the two spheres will have
lower but equal temperatures
Q.19 Two bodies A and B have thermal emissivities 0f 0.01 and 0.81 respectively. The
outer surface areas of the two bodies are the same. The two bodies emit total
radiation power at the same rate. The wavelength lB corresponding
to maximum spectral radiancy in the radiation from B is shifted from the wavelength corresponding to maximum spectral
radiancy in the radiation from A, by
1.0mm. If the
temperature of A is 5802K.
(a)
The temperature of B
is 1934K
(b)
lB = 1.5mm
(c)
The temperature of B
is 11604K
(d)
The temperature of B
is 2901K
Q.20 Heat is transferred most rapidly by the
process of
(a) Conduction (b) Convection (c) Radiation (d) combustion
Q.21 The high thermal
conductivity of metal is due to free electrons. The relevant electron property
:
(a) Its being charged (b) Convection
(c) Radiation (d) Combustion
Q.22 A
metallic rod is continuously heated at its two ends, the flow of heat through
the rod does not depend upon :
(a)
The area of cross-section of the rod (b) The
mass of the rod
(c) Time (d) The temperature gradient
Q.23 The quantity of
heat which crosses unit area of a metal plate during conduction depends upon :
(a)
The density of the metal
(b)
The temperature gradient perpendicular to the area
(c) The temperature to which the metal
is heated (d) The area of the metal plate
Q.24 The
coefficient of thermal conductivity of a metal depends on :
(a) Temperature difference between the
two sides (b) Thickness of the metal
(c) Area of the plate (d) None of the above
Q.25 The
S.I. unit of thermal conductivity is :
(a) Js-1mK-1 (b) Js
m-1K-1 (c) Js m-1K (d) J s-1 m-1 K-1
Q.26 If
K and s respectively
are the thermal and electrical conductivities of a metal at a absolute
temperature T, then :
(a) K/sT = constant (b) K/s = constant
(c) K/T = constant (d) KL = constant
Q.27 Two end of rods of length L and radius r
of the same material are kept at the same temperature. Which of the following
rods conducts most heat :
(a) L = 50 cm, r = 1 cm (b) L = 100 cm, r = 2 cm
(c) L = 25 cm, r = 0.5 cm (d) L = 75 cm, r = 1.5 cm
Q.28 A 2 cm thick slab of commercial thermocole,
100 cm2 in cross-section and having thermal conductivity 2 ´ 10-4
cal sec-1 cm-1 (C°)-1 has insulating regions differing by 100°C. The quantity
of heat flowing through it in a day will be :
(a) 20.4 kcal (b) 43.2
kcal (c) 86.4 kcal (d) 63.6
kcal
Q.29 One end of copper rod of length 1.0 m
and area of cross-section 10-3 m2 is immersed in boiling
water and the other end in ice. If the coefficient of thermal conductivity of
copper is 92 cal/m s C° and the latent
heat of ice is 8 ´ 10-4
cal/kg, then the amount of the ice which will melt in one minute is :
(a) 9.2 ´ 10-3 kg (b) 8 ´ 103 kg
(c) 6.9 ´ 10-3 kg (d) 5.4 ´ 10-3 kg
Q.30 Four identical copper cylinders are painted; if they are all
heated to the same temperature and left in vacuum, which will cool most
rapidly.
(a) Painted shiny white (b) Painted rough black
(c) Painted shiny black (d) Painted rough white
Q.31 A
polished metal with rough black spot on it is heated to about 1400 K and
quickly taken to a dark room. Which one of the following statements will be
true?
(a)
The spot will appear brighter than the plate
(b)
The spot will appear darker than the plate
(c)
The spot and plate will be equally bright
(d)
The spot and plate will not be visible in dark
Q.32 A piece of red glass when
heated in dark to red hot state will appear to be :
(a) White (b) Red (c) Green (d) Invisible
Q.33 Fraunhofer lines in the spectrum of sun are
explained by :
(a) Wien’s law (b) Planck’s
law (c) Newton’s law (d) Kirchhoff’s law
Q.34 The total
radiation emitted by a perfectly black body is proportional to :
(a)
Temperature on ideal gas scale (b) Fourth
root of temperature on ideal gas scale
(c) Fourth power of temperature on ideal gas
scale
(d) Square of
temperature on ideal gas scale
Q.35 If the temperature of the sun is
doubled, the rate of energy received on earth will be increased by a factor of
:
(a) 2 (b) 4 (c) 8 (d) 16
Q.36 A black body at a high temperature T K
radiates energy at the rate E watt/m2; when the temperature falls to (T/2) K
the radiated energy will be :
(a) E/4 (b) E/2 (c) 2E (d) E/16
Q.37 The temperature
of a body is increased from 27°C to 127°C. The radiation
emitted by it increase by a factor of :
(a) (256/81) (b) (15/9) (c) (4/3) (d) (12/27)
Q.38 According to Newton’s law of cooling
(provided the difference of temperature is small) the rate of loss of heat is
proportional to :
(a)
The excess temperature (b) The square of the excess temperature
(b)
The cube of the excess temperature (d) The fourth
power of the excess temperature
Q.39 A
body in a room cools from 90°C to 80°C in 5 minute. The time
taken to cool from 70°C to 60°C is :
(a) 5
minute (b) Less than 5 minute
(c) More
than 5 minute
(d) Less or
more than 5 minute depending on the nature of the liquid.
Q.40 In a room where the temperature is 30°C a body cools from 61°C to 59°C in 4 minute. The time
taken by the body to cool from 51°C
to 49°C will be :
(a) 4 minute (b) 6 minute (c) 5 minute (d) 8 minute
Q.41 A pan filled with hot food cools from
500°C to 49.9 C in 5 sec. How
long will it take to cool from 40.0 °C
to 39.9°C if the room temperature is
30°C?
(a) 2.5 s (b) 10 s (c) 20
s (d) 5
s
Q.42 As the
temperature of a black body increases, the wavelength of the emitted radiation
of maximum intensity
(a) Increases (b) Decreases
(c) Remains unchanged (d) Depends
on the material of the black body
Q.43 According to
Wien’s displacement law :
(a) Increases (b) Decreases
(c) Remains
unchanged (d) Depends
on the material of the black body
Q.44 The intensity of radiation emitted by the sun has its maximum
value at a wavelength of 510 nm and that emitted by the North Star has the
maximum value at 350 nm. If these stars behave like black bodies, th4en the
ratio of the these stars bodies, then the ratio of the surface temperature of
the Sun and the North Star is :
(a) 1.46 (b) 0.69 (c) 1.21 (d) 0.83
Q.45 A black body is at a temperature of 2800K. The energy of
radiation emitted by this object with wavelength between 499nm and 500nm is U1,
between 999 nm and 1000nm is U2 and between 1499nm and 1500nm is U3.
The Wein’s constant, b =2.88 x 106nm –K. Then:
(a) U1 =0 (b) U3 =0 (c) U1
>U2 (d) U2 >U1
Q.46 A spherical black body with
a radius of 12cm radiates 450W power at 500K. if the radius were halved and the temperature doubled, the
power radiated in watt would be
(a) 225 (b) 450 (c) 900 (d) 1800
Q.47 A black body at a temperature of 1640 K has the wavelength
corresponding to maximum emission equal to
1.75 m. Assuming the moon to be a
perfectly black body, the temperature of the moon, if the wavelength
corresponding to maximum emission is 14.35m is :
(a) 100K (b) 150 K (c) 200 (d) 250
Q.48 According
to Newton’s law of cooling, the rated cooling of a body is proportional to (Dq)n, when Dq is the difference of the
temperature of the body and the surroundings and n is equal to
(a)
Two (b) three (c) four (d) one
Q.49 In the Ingen Hauze’s experiment the was melts upto length 10 and
25 cm on two identical rods of different materials. The ratio of thermal
conductivities of the two materials is :
(a) 1 : 6.25 (b) 625 : 1 (c) 1 : Ö2.5 (d) 1
: 2.5
Q.50 A black body is at a
temperature 300 K. It emits energy at a rate, which is proportional to :
(a) 300 (b) (300)3 (c) (300)2 (d) (300)4
Q.51 Two spheres of the same material have radii 1m and
4m and temperature 4000K and 2000 K respectively. The ratio of the energy radiated
per second by the first sphere to that by the second is :
(a) 1 : 1 (b) 16
: 1 (c) 4
: 1 (d) 1 : 9
Q.52 Infrared
radiation is detected by :
(a) spectrometer (b) pyrometer (c) nanometer (d) photometer
Q.53 A hot and a cold body are kept in vacuum separated from each
other. Which of the following will cause decrease in temperature of the hot
body?
(a) Radiation (b) Convection
(c) Conduction (d) Temperature remains unchanged
Q.54 A black body at 1227°C emits radiation with
maximum intensity at a wavelength of 5000Å. If the temperature of the body is
increased by 1000°C, the maximum intensity
will be observed at :
(a) 4000 Å (b) 5000
Å (c) 6000
Å (d) 3000
Å
1.
|
(c)
|
2.
|
(b)
|
3.
|
(d)
|
4.
|
(b)
|
5.
|
(b)
|
6.
|
(c)
|
7.
|
(a)
|
8.
|
(c)
|
9.
|
(a)
|
10.
|
(a)
|
11.
|
(a)
|
12.
|
(b)
|
13.
|
(c)
|
14.
|
(a)
|
15.
|
(c)
|
16.
|
(a), (d)
|
17.
|
(a)
|
18.
|
(a), (b)
|
19.
|
(a), (b)
|
20.
|
(c)
|
21.
|
(c)
|
22.
|
(b)
|
23.
|
(b)
|
24.
|
(d)
|
25.
|
(d)
|
26.
|
(a)
|
27.
|
(b)
|
28.
|
(c)
|
29.
|
(c)
|
30.
|
(b)
|
31.
|
(a)
|
32.
|
(d)
|
33.
|
(d)
|
34.
|
(c)
|
35.
|
(d)
|
36.
|
(d)
|
37.
|
(a)
|
38.
|
(a)
|
39.
|
(a)
|
40.
|
(b)
|
41.
|
(b)
|
42.
|
(b)
|
43.
|
(b)
|
44.
|
(b)
|
45.
|
(d)
|
46.
|
(d)
|
47.
|
(c)
|
48.
|
(d)
|
49.
|
(a)
|
50.
|
(d)
|
51.
|
(a)
|
52.
|
(b)
|
53.
|
(a)
|
54.
|
(d)
|
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