Q.1
A thin square steel plate with each side equal to 10cm is heated by a blacksmith. The rate of radiated energy by the heated plate is 1134 watts. The temperature of the hot steel plate is... ( stefan's constant σ = 5.67×10-8 watt meter-2 K-4, emissivity of the late = 1 ) [ PMT 1995]
  • a) 1000 K
  • b) 1189 K
  • c) 2000 K
  • d) 2378 K
Q.2
If the colour of star is changing from red to blue it means [ RajPMT 1996]
  • a) The star is going away from the earth
  • b) The star is coming near the earth
  • c) The star is stationary
  • d) Non of the above
Q.3
If a liquid is heated in space under no gravity , the transfer of heat will take place by process of [ Raj.PMT 1996]
  • a) conduction
  • b) convection
  • c) Radiation
  • d) Cannot be heated in absence of gravity
Q.4
A body radiates energy 5W at temperature of 127°. If the temperature is increased to 927 °C then it radiates energy at the rate of [ BHU 1995]
  • a) 410 W
  • b) 81 W
  • c) 405 W
  • d) 200W
Q.5
If the temperature of sun is doubled [ raj. PMT 1996]
  • a) Emission will become four times
  • b) Emission will become double
  • c) Mainly it will emit ultra violet radiations
  • d) Mainly it will emit infra red radiations
Q.6
Two rods of same length and material transfers given amount of heat in 12 sec, when they are joined end to end. But when they are joined lengthwise, then they will transfer same heat in same conditions in [ BHU 1998]
  • a) 24 sec
  • b) 3 sec
  • c) 1.5 sec
  • d) 48 sec
Q.7
An iron tyre is to be fitted on a wooden wheel 1.0 m in diameter, the diameter of the tyre is 6 mm smaller than that of the wheel. The tyre should be heated so that its temperature increases by a minimum of :.. ( coefficient of expansion of iron is 3.6×10-5 per °C) [ CPMT 1989]
  • a) 167°C
  • b) 334°C
  • c) 500 °C
  • d) 1000 °C
Q.8
A metal ball immersed in alcohol weighs W1 at 0°C and W2 at 95°C. the coefficient of cubical expansion of the metal is less than that of alcohol. Assuming that the density of the metal is large compared to that of alcohol, it can be shown that [ CPMT 1998]
  • a) W1 > W2
  • b) W1 = W2
  • c) W1 < W2
  • d) W2 = W1 /2
Q.9
Two rods of lengths l1 and l2 are made of materials whose coefficients of linear expansions are α1 and αIf the difference between the two lengths is independent of temperature [ EAMCET 1995]
  • a)
    ch-8_qn-248choice_img_no1.png
  • b)
    ch-8_qn-248choice_img_no2.png
  • c)
    ch-8_qn-248choice_img_no3.png
  • d)
    ch-8_qn-248choice_img_no4.png
Q.10
The temperature of an isotropic cubical solid of length L, density d and coefficient of expansion α per degree Kelvin, is raised by 10°C. Then, at this temperature, to a good approximation ..[ IIT 1995]
  • a) Lengt is L(1 +10α)
  • b) Total surface area is L2 ( 1 +20α)
  • c) density is d (1 + 30α)
  • d) density is d/(1+30α)
Q.11
A ring shaped piece of metal is heated . If the material expands, the hole will [ EAMCET 1994]
  • a) expand
  • b) contract
  • c) expand or contracts depending on the width of ring
  • d) expand or contract depending on the value of the coefficient of expansion
Q.12
A pendulum of brass has period of 1 sec. at 20°C. Coefficient of linear expansion of brass is 1.93×10-5 / °C. The clock gets delayed in week at 30° by ..[ Raj.PET 1997]
  • a) 8 sec
  • b) 58s
  • c) 224 s
  • d) 504 s
Q.13
A beaker is filled with water at 4°C. At one time the temperature is increased by few degrees above 4°C and at another time it is decreased by few degree below 4°C. One shall observe that
  • a) the level remains constant in each case
  • b) water overflows in both cases
  • c) water overflows in the latter case, while its level comes down in the previous case
  • d) in previous case water overflows while in latter case its level comes down
Q.14
A container of volume 1 m3 is divided into two equal compartments by a partition. One of these compartments contains an ideal gas at 300K. The other compartment is vacuum. The whole system is thermally isolated from its surroundings. The partition is removed and gas expands to occupy the whole volume of the container. It temperature now would be ..[ UGET 1995]
  • a) 300 K
  • b) 250K
  • c) 200 K
  • d) 100 K
Q.15
A long cylindrical vessel of volume V and linear coefficient of expansion α contains a liquid. The level of liquid has not changed then coefficient of cubical expansion of liquid is .. [ EAMCET 1986]
  • a) (V -α) / V
  • b) (V + α) / V
  • c) V / (V -α)
  • d) 3α
Q.16
A rod of length 30 cm made of material A expands by 0.075 when its temperature is raised from 0°C to 100 °C. Another rod of a different metal B having same length expands by 0.045cm, for the same change in temperature. A third rod of the same length is composed of two parts, one of metal A and other of metal B. This rod expands by 0.065 cm, for the same change in temperature. The portion made of metal A has the length [ CPMT 1991]
  • a) 20 cm
  • b) 10 cm
  • c) 15 cm
  • d) 18 cm
Q.17
A bimetallic strip having two strips each of thickness 'd' are heated by Δt°C. If their coefficient of linear expansions are α1 and α2 respectively, then on heating they will bend in the form of arc whose radius is
  • a)
    ch-8_qn-257choice_img_no1.png
  • b)
    ch-8_qn-257choice_img_no2.png
  • c)
    ch-8_qn-257choice_img_no3.png
  • d)
    ch-8_qn-257choice_img_no4.png
Q.18
The moment of inertia of an object is l and the coefficient of linear expansion is α. If the temperature of the object is changed by Δθ , then the change in its moment of inertia is
  • a) αlΔθ
  • b) 2αlΔθ
  • c)4αlΔθ
  • d)αlΔθ/2
Q.19
A heat flux of 4000 J/s is to be passed through a copper rod of length of 10cm and area of cross section 100 sq. cm. The thermal conductivity of copper is 400 W/m. °C. The two ends of this rod must be kept at a temperature difference of [ MPPMT 1999]
  • a) 1°C
  • b) 10°C
  • c)100 °C
  • d)1000 °C
Q.20
A sphere of density ρ, specific heat capacity c and radius r, is hung by a thermally insulated thread in an enclosure which is kept at lower temperature than the sphere. the temperature of the sphere starts to drop at the rate which depends up on the temperature difference between the sphere and the enclosure and the nature of the surface of the sphere and is proportional to ..
  • a) c/ r3ρ
  • b) 1 / r3ρc
  • c) 3r3ρc
  • d) 1 / rρc
Q.21
The following four wires are made of the samematerial. Which of these will have the largestextension when the same tension is applied?
  • a) Length = 50 cm, diameter = 0.5 mm
  • b) Length = 100 cm, diameter = 1 mm
  • c) Length = 200 cm, diameter = 2 mm
  • d) Length = 300 cm, diameter = 3 mm
Q.22
The wettability of a surface by a liquid dependsprimarily on
  • a) Viscosity
  • b) Surface tension
  • c) Density
  • d) Angle of contact between the surface and theliquid
Q.23
Copper of fixed volume 'V' is drawn intowireof length 'L '.When thiswire is subjected to aconstant force 'F', the extension produced in the wire in 'ΔL '.Which of the following graphsis a straight line?[ AIMPT 2014]
  • a) ΔL versus 1/L2
  • b) ΔL versus L
  • c) ΔL versus 1/L
  • d) ΔL versus L2
Q.24
Acertain number of spherical drops of a liquidof radius 'r' coalesce to forma single drop ofradius 'R' and volume 'V'. If 'T' is the surfacetension of the liquid, then … [ AIPMT 2014 ]
  • a)
    ch-8_qn-264choice_img_no1.png
  • b) Energy is neither released nor absorbed
    ch-8_qn-264choice_img_no3.png
  • c)
    ch-8_qn-264choice_img_no4.png
  • d)
Q.25
The approximate depth of an ocean is 2700 m. The compressibility of water is 45.4 × 10-11 Pa-1 anddensity of water is 103 kg/mWhat fractional compression of water will be obtained at the bottom ofthe ocean?
  • a) 1.4 × 10-2
  • b) 0.8 × 10-2
  • c) 1.0 × 10-2
  • d) 1.2 × 10-2
Q.26
A wind with speed 40 m/s blows parallel to the roof of a house. The area of the roof is 250 mAssuming that the pressure inside the house is atmospheric pressure, the force exerted by thewind on the roof and the direction of the force will be : … [ AIPMT 2015] (ρair = 1.2 kg/m3)
  • a) 2.4 × 105 N, downwards
  • b) 4.8 × 105 N, downwards
  • c) 4.8 × 105 N, upwards
  • d) 2.4 × 105 N, upwards
Q.27
The cylindrical tube of spray pump has radius R, one end of which has n fine holes, each of radius r. If the speed of the liquid in the tube is V, the speed of the ejection of the liquid through the holes is…[ Re. AIPMT 2015]
  • a)
    ch-8_qn-267choice_img_no1.png
  • b)
    ch-8_qn-267choice_img_no2.png
  • c)
    ch-8_qn-267choice_img_no3.png
  • d)
    ch-8_qn-267choice_img_no4.png
Q.28
The Young's modulus of steel is twice that of brass. Two wires of same length and of same area of cross section, one of steel and another of brass are suspended from the same roof. If we want the lower ends of the wires to be at the same level, then the weights added to the steel and brass wires must be in the ratio of : …[Re AIPMT 2015]
  • a) 1 : 1
  • b) 1:2
  • c) 2:1
  • d) 4:1
Q.29
Water rises to height 'h' in capillary tube. If the lengthof capillary tube above the surface of water is madeless than 'h', then – [ Re AIPMT 2015] Solution:
  • a) water does not rise at all.
  • b) water rises upto the tip of capillary tube and thenstarts overflowing like afountain.
  • c) water rises upto the top of capillary tube and stays there without overflowing.
  • d) water rises upto a point a little below the topand stays there.
Q.30
The value of coefficient of volume expansion ofglycerin is 5 × 10-4 K-The fractional change inthe density of glycerin for a rise of 40°C in itstemperature, is :-
  • a) 0.010
  • b) 0.015
  • c) 0.020
  • d) 0.025
0 h : 0 m : 1 s