Question

When I shine dim green light on a metal surface, some electrons are ejected from the surface. The most energetic ejected electrons have very little energy.
How can we increase the energy of the most energetic ejected electrons?

• A. Shine bright red light on the surface
• B. Shine bright green light on the surface
• C. Shine dim red light on the surface
• D. Shine dim purple light on the surface
• E. Shine a red strobe light on the surface

Answer 1

Answer: (B)

Shine bright green light on the surface

By the experimental study of photoelectric effects , we know that energy of emitted electrons depends upon the frequency (energy of photons) of incident light on metal surface . therefore if we increase the frequency of incident light , the energy of ejected electrons also increases , that can be done by using bright green light instead of dim green light .