In a photoelectric effect experiment, monochromatic ultraviolet radiation of wavelength 280 nm280\text{ nm}280 nm is incident on a clean metal surface. To reduce the resulting photoelectric current to zero, a stopping potential of 1.45 V must be applied.
The radiation source is then replaced by one emitting radiation of wavelength 210 nm210\text{ nm}210 nm.
What is the new stopping potential required to reduce the photoelectric current to zero?
1.09 V1.09\text{ V}1.09 V
1.93 V1.93\text{ V}1.93 V
2.93 V2.93\text{ V}2.93 V
8.91 V8.91\text{ V}8.91 V
