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NEET-XII-Physics

exam-1 year:2016

with Solutions -
Qstn# 11 Prvs-QstnNext-Qstn
  • #11
    A refrigerator works between 4°C and 30°C. It is
    required to remove 600 calories of heat every
    second in order to keep the temperature of the
    refrigerated space constant. The power required is:
    (Take 1 cal = 4.2 Joules)
    (1) 2.365 W
    (2) 23.65 W
    (3) 236.5 W
    (4) 2365 W
    digAnsr:   3
    Ans : 3
    Sol.
    2 2
    1 2
    Q T
    W T - T
     = = (Where Q2 is heat removed)
    &implies;
    600 4.2 277
    W 303 - 277

    =
    &implies; W = 236.5 joule
    &implies; Power = =
    W 236.5 joule
    t 1sec = 236.5 watt.