Physics 0625 · IGCSE · Transfer of thermal energy

Transfer of thermal energy — practice question

A liquid flows along pipes inside a refrigerator. As the inside of the refrigerator becomes cooler, the liquid itself becomes warmer. That warmed liquid is then sent through pipes on the outside of the refrigerator so that it can lose heat before it returns through the refrigerator again. The diagrams illustrate two possible arrangements of the external cooling pipes. In one arrangement, copper rods, known as fins, are fixed to the pipes. The outer pipes and fins may be painted silver or black. Which arrangement of the external pipes will cool the liquid most rapidly?

  • Apainted black with fins
  • Bpainted black without fins
  • Cpainted silver with fins
  • Dpainted silver without fins

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