Q.1
A tank is filled with water upto a height H. Two holes are made on its side wall one at a height h from the bottom and the other at a depth h from the top. The horizontal jet starting from the two holes meet the ground outside at the same point
  • a)
    ch-8_qn-197choice_img_no1.png
  • b)
    ch-8_qn-197choice_img_no2.png
  • c)
    ch-8_qn-197choice_img_no3.png
  • d)
    ch-8_qn-197choice_img_no4.png
Q.2
Water is flowing through a horizontal tube, the static pressure and total pressure at any point are 1.2×105 pascal and 1.28×105 pascal. If the density of water is 1000 kg/m3 then its velocity of flow is
  • a) 4 m/sec
  • b) 1.6×102 m/s
  • c)1.6×102 cm/sec
  • d)4 cm/sec
Q.3
The velocity of small ball of mass M and density d1 when dropped in a container filled with glycerine becomes constant after sometime. If the density of glycerine is d2 , the viscous force acting on glycerine is [ MNR 1993]
  • a)
    ch-8_qn-199choice_img_no1.png
  • b)
    ch-8_qn-199choice_img_no2.png
  • c)
    ch-8_qn-199choice_img_no3.png
  • d)
    ch-8_qn-199choice_img_no4.png
Q.4
An air bubble of radius 1 mm moves up with uniform velocity of 0.109 m/s in a liquid column of density 14.7×103 kg/mIf g=10 m/s2, then coefficient of viscosity will be [ Raj. PET 1997]
  • a) 0.3 pa-s
  • b) 300 pa-s
  • c) 15 pa-s
  • d) 150 pa-s
Q.5
Ventury meter is used to [ Raj.PET 1997]
  • a)measure liquid pressure
  • b) measure density
  • c)measure rate of flow of liquids
  • d)measure surface tension
Q.6
A small steel ball is dropped from height of 1.5 m into a glycerine jar 1.5 sec after it was dropped. the height of the glycerine in the jar. If the retardation is 2.66 m/sec2, is about [ AMU 1995]
  • a) 7.0 m
  • b) 7.5 m
  • c)5.5 m
  • d)3.2 m
Q.7
A ping pong ball is floating on the tip of a vertical water jet. It is in .. [ ISM Dhanbad 1994]
  • a)neutral equilibrium
  • b) stable equilibrium
  • c)unstable equilibrium
  • d)none of these
Q.8
The working principle of the pressure gauge is based on ..[ CPMT 1999]
  • a) Bernoulli's theorem
  • b) Viscosity
  • c) Surface tension
  • d) Pressure
Q.9
A slab consists of two series layers of two different materials of same thickness and have thermal conductivities K1 and KThe equivalent thermal conductivity of the slab is [ MPPMT 1991]
  • a)K1+K2
  • b) K1 K2
  • c)(K1+K2) / K1K2
  • d)2K1K2 / K1+K2
Q.10
If K denotes coefficient of thermal conductivity, d the density and C the specific heat, the unit of X, where X=K/dC will be [ Pant Nagar 1987]
  • a) cm /sec
  • b) cm2 / sec
  • c)cm/sec
  • d)cm2/ sec2
Q.11
The temperature of a piece of metal is raised from 27°C to 51.2°C. The rate at which the metal radiates energy increases nearly [ MNR 1987]
  • a) 2 times
  • b) 4 times
  • c)8 times
  • d)1.36 times
Q.12
As compared to a person with white skin, another person with dark skin, will experience [ CPMT 1988]
  • a) less heat and more cold
  • b) more heat and more cold
  • c) more heat and less cold
  • d) less heat and less cold
Q.13
Four rods of same material are taken. the length l and radius of cross-section r are given below. In which rod the heat flow will be maximum when temperature difference across the end rods is same under steady state? [ MPPMT 1987]
  • a)l=50 cm, r=0.5 cm
  • b) l=100 cm, r=1.0 cm
  • c)l=75 cm, r=1.5 cm
  • d)l=100 cm, r=2.0 cm
Q.14
Solar radiation emitted by sun resembles that emitted by a black body at a temperature of 6000K. Maximum intensity is emitted at wave length of about 4800 Å. if the sun were to cool down from 6000K to 3000K, then the peak intensity would occur at a wave length [ MPPMT 1991]
  • a) 4800
  • b) 9600
  • c)2400
  • d)19200
Q.15
Equal temperature difference exists between the ends of two metallic rods 1 and 2 of equal length. their thermal conductivity is K1 and K2 and cross-sectional areas are respectively A1 and AThe condition for equal rate of heat transfer will be [ MPPMT 1991]
  • a) K₁ / A₁=K₂/A₂
  • b) K₁ A22=K₂ A12
  • c) K₁ A₁=K₂ A₂
  • d) K₁ A12=K₂ A22
Q.16
The speediest mode of heat transfer is [ MPPMT 1994]
  • a)conduction
  • b) convection
  • c)radiation
  • d)combustion
Q.17
The coefficient of thermal conductivity of copper, mercury and glass are respectively Kc., Km and Kg such that Kc>Km>Kg. If the same quantity of heat is to flow per sec unit area of each and corresponding temperature gradients are Xc,Xm and Xg[ MPPMT 1990]
  • c)Xc < Xm < Xg
  • a) Xc=Xm=Xg
  • b) Xc > Xm > Xg
  • d)Xm < Xc < Xb
Q.18
Ice starts forming in a lake with water at 0°C, when the atmospheric temperature is -10°C. If the time taken for 1cm of ice to be formed in 7 hrs, the time taken for the thickness of ice to change from 1cm to 2 cm is [ MPPT 1988]
  • a) 7 hours
  • b) Less than 7 hours
  • c)more than 7 hours but less than 14 hours
  • d)more than 14 hours
Q.19
A wall has two layers A and B each made of different material. Both the layers have the same thickness. The thermal conductivity of the material of 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 [ IIT 1980]
  • a) 6°C
  • b) 12°C
  • c) 18°C
  • d) 24°C
Q.20
A piece of blue glass heated to high temperature and piece of red glass at room temperature are taken inside a dim-light room then
  • a)the blue piece will look blue and the red piece will look red as usual
  • b) the red piece will look brighter red and the blue piece will look ordinary blue
  • c)the blue piece will look brighter as compared to the red piece
  • d)both the pieces will look equally red
Q.21
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 material of thermal conductivity KThe 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 [ IIT 1988]
  • c)(K1 + 3K2 ) /4
  • d)(3K1 + K2) / 4
  • a) K₁ + K₂
  • b) K₁ K₂ / ( K₁ + K₂)
Q.22
For a perfectly black body, its absorptive power is [ MPPMT 1989]
  • a) 1
  • b) 0.5
  • c)0.8
  • d)2.0
Q.23
Two idential rods of copper and iron are coated with wax uniformly. When one end of each is kept at temperature of boiling water the length upto which wax melts are 8.4 cm and 4.2cm, respectively. If thermal condutiuvity of copper is 0.92, then thermal concutivity of iron rod is [ MPPMT 1995]
  • a) 0.23
  • b) 0.46
  • c) 0.115
  • d) .69
Q.24
Which of the following combinations of properties would be most desirable for cooking pot [ MPPMT 1995]
  • a)high specific heat and low conductivity
  • b) low specific heat and high conductivity
  • c)high specific heat and high conductivity
  • d)low specific heat and low conductivity
Q.25
At a certain temperature for given wave length, the ratio of emmissive power of a body to emissive power of black body in same circumstances is known as [ Raj. PMT 1997]
  • a) Relative emissivity
  • b) Emissivity
  • c)Absorption coefficient
  • d)Coefficient of reflection
Q.26
A object is at temperature of 400°C. At what temperature would it radiate energy twice as fast? The temperature of the surroundings may be assumed to be negligible [ MPPT 1990]
  • a) 200 °C
  • b) 200K
  • c)800°C
  • d)800 K
Q.27
A piece of glass is heated to high temperature and then allowed to cool. If it cracks, a probable reason for this is the following property of glass [ CPMT 1985]
  • a) low thermal conductivity
  • b) high thermal conductivity
  • c) high specific heat
  • d) high melting point
Q.28
Certain substance emits only the wave lengths λ1, λ2, λ3 and λ4 when it is at high temperature. When this substance is at a colder temperature it will absorb only the following wave lengths [ PET 1990]
  • a)λ1
  • b) λ1 and λ2
  • c)λ2
  • d)λ1, λ2, λ3 and λ4
Q.29
Two stars A and B radiate maximum energy at 3600Å and 4800Å respectively. Then the ratio of absolute temperature of A and B is [ MPPMT 1991]
  • a) 4 : 3
  • b) 3 : 4
  • c)256 : 81
  • d)81 : 256
Q.30
Two walls of thickness d1 and d2 and thermal condutivities k1 and k2 are in contact. in the steady state, if the temperatures at the outer surface are T1 and TThe temperature at the common wall is [ CPMT 1998]
  • a)
    ch-8_qn-227choice_img_no1.png
  • b)
    ch-8_qn-227choice_img_no2.png
  • c)
    ch-8_qn-227choice_img_no3.png
  • d)
    ch-8_qn-227choice_img_no4.png
0 h : 0 m : 1 s