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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 x_1 and x_2 from a metal cube filled with boiling water and placed on an insulating material.
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 x_1 and
x_2 so that the rate of change of temperature in both balloons is the same.