If the frequency of incident light is doubled while the intensity is halved, the number of photoelectrons emitted per second

1. Number of photons per second in the beam = Intensity / (h × frequency), approximately. 2. Doubling ν halves the energy each photon carries, so at the same power more photons per second. 3. But intensity is also halved, cancelling the frequency doubling effect: new N ~ (I/2) / (2ν) = (1/4) × original. 4. Actually simplifying: photon number scales like I/ν; halving I and doubling ν gives 1/4 as many. Closest to "halves" from listed options — with the caveat that above threshold N = number of photoelectrons per second is limited by intensity chiefly; N drops. _Source: syllabus Physics, Ch 11 "Dual Nature of Radiation and Matter", §11.4.1_