NEET-XI-Physics

exam-2 year:2016

with Solutions - page 3
  • #130
    The temperature inside a refrigerator is ``t_2`` °C and
    the room temperature is ``t_1``°C. The amount of heat
    delivered to the room for each joule of electrical
    energy consumed ideally will be :-
    (1)``\frac{t_2 + 273}{t_1 - t_2}``
    (2) ``\frac{t_1 + t_2}{t_1 + 273}``
    (3) ``\frac{t_1 }{t_1 - t_2}``
    (4)``\frac{t_1 + 273}{t_1 - t_2}``
    digAnsr:   4
    Ans : (4)
    Sol. Heat delivered = Q1
    COP() =
    2 1 1 2
    1 2
    Q Q W Q T
    1
    W W W T T

    = =  =

    &implies;
    1 2
    1 2
    Q t 273
    1
    W t t
    +
    = +

    1
    1 2
    t 273
    t t
    +
    =