ICSE-VIII-Physics

06: Heat Energy Class 8 Physics

with Solutions -
  • #1
    Write true or false for each statement (a) Evaporation is rapid on a wet day.
    (b) Evaporation takes place only from the surface of liquid.
    (c) All molecules of a liquid take part in the process of evaporation.
    (d) Temperature of a liquid rises during boiling or vaporization
    (e) All molecules of a liquid take part in boiling.
    (f) Boiling is a rapid phenomenon.
    (g) All solids expand by the same amount when heated to the same rise in temperature.
    (h) Telephone wires are kept tight between the two poles in winter.
    (i) Equal volumes of different liquids expand by the different amount when they are heated to the same rise in temperature.
    (j) Solids expand the least and gases expand the most on being heated.
    (k) A mercury thermometer makes use of the property of expansion of liquids on heating.
    (l) Kerosene contracts on heating.
    Ans : (a)
    False (b)
    True (c)
    False (d)
    False (e)
    True (f)
    True (g)
    False (h)
    True (i)
    True (j)
    True (k)
    True (l)
    False
  • #1-a
    Evaporation is rapid on a wet day.
    Ans :
    False
  • #1-b
    Evaporation takes place only from the surface of liquid.
    Ans :
    True
  • #1-c
    All molecules of a liquid take part in the process of evaporation.
    Ans :
    False
  • #1-d
    Temperature of a liquid rises during boiling or vaporization
    Ans :
    False
  • #1-e
    All molecules of a liquid take part in boiling.
    Ans :
    True
  • #1-f
    Boiling is a rapid phenomenon.
    Ans :
    True
  • #1-g
    All solids expand by the same amount when heated to the same rise in temperature.
    Ans :
    False
  • #1-h
    Telephone wires are kept tight between the two poles in winter.
    Ans :
    True
  • #1-i
    Equal volumes of different liquids expand by the different amount when they are heated to the same rise in temperature.
    Ans :
    True
  • #1-j
    Solids expand the least and gases expand the most on being heated.
    Ans :
    True
  • #1-k
    A mercury thermometer makes use of the property of expansion of liquids on heating.
    Ans :
    True
  • #1-l
    Kerosene contracts on heating.
    Ans :
    False