Molecular Physics | Thermodynamics Answers

Bricks have a thickness of 12cm. If an external wall of a house measures 10m x 15m, calculate the rate of heat exchange through this wall if the inside temperature is 20 degrees celsius and the outside temperature is 5 degrees celsius

why won't heat be conducted along the length of the metal rod when the whole length of the rod has a uniform temprature?

1Which of the following helps to determine whether a body will be in thermal equilibrium with another body?

thermal energy

zeroth law of thermodynamics

numerical scale

first law of thermal thermodynamics


2A thermocouple works on the principle of --------------------

variation of e.m.f with temperature

variation of volume with temperature

variation of pressure with temperature
variation of resistance with temperature


3The fundamental interval of a thermometric scale refers to ---------------------

triple point of water

difference between upper and lower fixed points

ratio of the upper to the lower fixed point

temperature of steam at standard atmospheric pressure


4The ice and steam points on a thermometer correspond to X and 50mm respectively. A temperature of 60degree celcius corresponds to 52mm on the thermometer. Calculate the value of X

4 mm

8 mm

10 mm
20 mm


5A railway line is laid with 10m length of rail on a day when the temperature is 2:50oC . There is a gap of 0.5cm between the rails. Find the temperature at which the gap will close.

27:00oC

32:50oC

41:70oC

44:20oC



6In an experiment involing an ideal gas the pressure (P) of the gas is plotted against the reciprocal of the volume ( 1/V ) of the gas at constant temperature. The graph is------------

a straight line with negative slope and intercepts on both axes

a straight line with a positive slope and passes through the origin
a curve which is asymptotic to both axes

a parabolic curve



7A platinium resistance thermometer has resistance of 52.5 ohms and 9.75 ohms at 0 degrees celcius and 100 degrees celcius respectively. When the resistance is 8.25 ohms, find the temperature

63:6oC

66:7oC

75:0oC

84:6oC



8The choice of thermometric liquids in a thermometer should depend on the following properties except:

must be opaque

must have a low melting point

must have a high specific heat capacity

must have a high coefficient of expansion


9A square plate of side 10 cm is made of a metal of linear expansivity 2Â10À5 /K. As the plate is heated from 30o C to 100o , the area of one face of the plate will increase to -------------

105:6cm2

104:2cm2

102:8cm2

101:4cm2



10The equation PaVbTc=constant reduce to Boyle’s law if

a=1,b=0,c=0

a=1,b=1,c=0

a=0,b=0,c=1

a=1,b=1,c=1



11The product of pressure (P) and volume (V) has the dimension or unit of ---------------------------

force

power

impulse

work



12The S.I unit of heat capacity is -------------------

joules

joule per kilogramme
joule per Kelvin

kilogramme per joule


13The process by which a substance changes directly from solid state to gaseous state at any temperature is called

Van der Waals process
sublimation

Newton’s law of cooling
evaporation



14A gas occupies a certain volume at 27 degree celcius.If it is heated at constant pressure, its volume is exactly doubled at a temperature of ----------------------

54 degrees celcius

219 degrees celcius
327 degrees celcius
600 degree celcius



15If the specific heat capacity of water initially is 4:2Â103 per kg per K and g=10m=s2 , the difference in temperature of water between the top and bottom of a 210 m high water fall is ----------

0:05oC

0:5oC

1:0oC

4:2oC



16A person suffers a more severe burn from steam than from boiling water because -------------------

steam is at higher temperature than boiling water

steam spreads more easily over the skin than boiling water

steam penetrates more deeply into the skin than boiling water

steam possesses greater heat energy per unit mass than boiling water at the same temperature


17A change of state is often accompanied by a change in (I) temperature (II) density (III) internal energy (IV) mass. Which of these is correct?

I and II

II and III

III and IV
I and IV



18When the pressure of the vapour on top of an enclosed liquid is equal to the pressure of the atmosphere, the liquid is at its ---------

boiling point

dew point

freezing point
melting point



19One of these is NOT a factor that can affect the rate of evaporation

temperature

pressure

volume of liquid
air dryness



20The Van der Waals equation for real gases is given as

p+av2=RT

(p+aV2)b=RT

(PÀaV2)b=RT

(P+aV2)(VÀb)=RT

an iron block of mass 500 grams is dropped in styrofam cup of negligible mass containing 100 grams of water @ 50 celsius , if inital temperature of iron is 400 celsius, what is the final temperature and how much water remains in the cup?
Cwater=4186J/(kg*k), C iron=448J/(kg*k), Csteam=2010J/(kg*k), Lv(water)= 22.6*10^5J/kg

Some small aluminum riverts of total mass 170g and at 100°C are emptied into a hole in a large block of ice at 0°C.
a) What will be the final temperature of the riverts?
b) How much ice will melt?

how the winds currents are generated ? explain.

Nora, whose mass is 50.0 kg, stays out skiing for too long and her body temperature drops by 2.00°C. What is the amount of heat lost from Nova’s body? (chuman body = 3470 J/kg°C)

To what pressure must a gas be compressed in order for it to fit 400 cubic meters ( at standard pressure) of it into 3.00 cubic meter tank?

A kangaroo is capable of jumping to a height of 2.62 m. determine the takeoff speed of the kangaroo.

http://www.laserpablo.com/teacherresources/files/labs/TempofaFlame.pdf
I need help with this whole lab
the mass of the ball is 1.7
the initial temperature of the water was 25 degrees c
the mass of water in 250 ml