Calculate the maximum ke and velocity of an electron from zinc by a 275nm photon

Kinetic energy:

Velocity:

Explanation:

From the equations of the photo-electric effect,

We know:

Where,

1. is the Planck's constant which is

2. are the frequency of light emitted and threshold frequencies respectively.

3. is the kinetic energy of the electrons emitted.

By fact, we come to know that the threshold frequency of Zn is 300nm

And also

Where ,

1. is the speed of light

2. is the wavelength.

Thus,

Now to find velocity:

answerca air mass;