Yes, you are correct. When we change the source light from 500 nm wavelength to 450 nm wavelength at the same intensity level, more electrons would be emitted compared to the initial condition.
This is because the energy of each photon of light is directly proportional to its wavelength. Photons with shorter wavelengths (like 450 nm) have higher energy compared to photons with longer wavelengths (like 500 nm).
According to the photoelectric effect, electrons can only be emitted from a metal surface when they absorb enough energy from incident photons to overcome the metal's work function. The work function is the minimum amount of energy required by an electron to be released from the metal.
Since the 450 nm light has higher energy photons compared to the 500 nm light, these higher energy photons will be able to transfer more energy to the electrons upon collision. As a result, more electrons will gain the necessary energy to be emitted from the metal surface. Therefore, the number of emitted electrons will increase when we change the source light to 450 nm at the same intensity level.