JEE Advanced 2020 Full Test 2 Paper 2

In a slow reaction, heat is being evolved at a rate about 10mW in a liquid. If the heat were being generated by the decay of ‌32P, a radioactive isotope of phosphorus that has half-life of 14 days and emits only beta-particles with a mean energy of 700KeV. The number of ‌32P atoms in the liquid is A×77×1015 find a:
[Take: ln‌2=0.7]