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Figure 4 shows two identical balloons A and B. The balloons were filled with equal amounts of the same type of gas. The balloons are suspended at a distances x1 and x2 from a metal cube filled with boiling water and placed on an insulating material.
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The face of the cube towards A is bright and shiny and the face towards B is dull black. State with reason the adjustments that should be made on the distances x1 and
x2 so that the rate of change of temperature in both balloons is the same.