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5 marksThermal Measurements

CSEC Physics · 1991 · Paper 2 · Question 1(c)

Opening the refrigerator door repeatedly allows warm room air to enter, which then must be cooled down.

Given the refrigerator volume of 0.40 m³, air density of 1.29 kg m⁻³, specific heat capacity of air of 600 J kg⁻¹ K⁻¹, and 1 kW h = 3.6 × 10⁶ J, calculate the electrical energy in kilowatt-hours needed to cool the air inside from 30 °C to 5 °C.

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Other parts of this question

  1. 1(a)(i)Calculate the energy consumption of the refrigerator per month.[3 marks]
  2. 1(a)(ii)Assuming 1 month = 30 days, determine the average power consumption of the refrigerator in watts.[3 marks]
  3. 1(b)(i)State the names of each of the three pins.[3 marks]
  4. 1(b)(ii)Explain why the manufacturer insists the earth/third pin must not be removed, even though the refrigerator functions with two pins.[2 marks]

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