In a device for measuring the power of electromagnetic radiation, the radiation energy is completely absorbed in the cylinder AB (Fig. 68), through which the liquid is driven at a certain speed. Determine the energy absorbed in the cylinder per unit time if it is known that the temperatures of the liquid in the tubes at the inlet and outlet of the cylinder are equal to T1 and T2, respectively. The absorption process is considered to be steady. Neglect the change in the density of the liquid and its specific heat capacity with temperature. The density of the liquid is p, the specific heat is C, the flow rate of the liquid is v, and the cross-sectional area of the tubes is S.

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