Solution
Related Formula
Etotal = P × t Elight = Etotal × Efficiency Elight = n × hνCore Logic
Power of bulb = 150 W = 150 J/s. Energy emitted in 1 second (t = 1 s) = 150 J. Energy converted to light = 8% of 150 J.
Elight = (150 × 8)/(100) = 12 JGiven energy of one photon (hν) = 4.42 × 10⁻¹⁹ J.
Step 1: Calculate number of photons
n = Elighthν n = 124.42 × 10⁻¹⁹ n ≈ 2.714 × 10¹⁹Pattern Recognition
Watts = Joules/second. When finding photons per second, first reduce the total wattage by the efficiency percentage to find the "effective" light power, then divide by the energy of a single photon.
Chapter Mix
Class 11 Chemistry: Structure of Atom