Photoelectric Effect

The stopping potential is related to the energy of the photons by the equation: where: is the threshold wavelength, is Planck's constant, and is the speed of light. For , the stopping potential is , and for , it is . Solving this equation will give the threshold wavelength as .

The rate of photoelectron emission depends directly on the intensity of the incident light. Intensity is proportional to the number of photons striking the surface, which in turn determines the number of photoelectrons emitted. According to the photoelectric effect, each photon has a certain energy that is transferred to an electron. If the energy of the photon is above the work function of the material, electrons are ejected. The higher the intensity of light, the greater the number of photons striking the surface, leading to a higher rate of photoelectron emission.

However, it is important to note that the frequency of the light affects the energy of each individual photon, and only photons with energy greater than or equal to the work function can emit electrons. But the rate of emission itself is governed by the intensity, not frequency.

Hence, the correct answer is (c).