But I am a couple of powers of in the mark scheme it says 3.33*10^16 What am I doing wrong?
Where did you get 15 * 10^6 from? I believe it is supposed to be 15 * 10^-3, as it is mW (milliwatts) not MW (megawatts). This should give you the correct answer.
Where did you get 15 * 10^6 from? I believe it is supposed to be 15 * 10^-3, as it is mW (milliwatts) not MW (megawatts). This should give you the correct answer.