Problem 2. A sodium photoelectric surface with work function 2.3eV is illuminated and emits electrons. The electrons travel toward a negatively charged cathode and complete a circuit. The potential difference supplied by the power supply is increased, and when it reaches 4.5V, no electrons reach the cathode. a) For the electrons emitted from the sodium surface, calculate the following. i. The maximum kinetic energy ii. The electron speed at this maximum kinetic energy b) Calculate the wavelength of the radiation that is incident on the sodium surface. c) Calculate the minimum frequency of light that will cause photoemission from this sodium surface.

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.