Anickel crystal's work function is measured to be 5.22 ev at 25°c. as the temperature increases by 300°c, the work function drops by 50 mev.

by how much does this shift the threshold wavelength for photoelectric emission?

The shift the threshold wavelength for photoelectric emission is 2.317 nm.

Explanation:

Given that,

Work function = 5.22 eV

Temperature = 25°C

Increased temperature = 300°C

Drop work function = 50 meV

We need to calculate the shift the threshold wavelength for photoelectric emission

Using formula of work function

The wavelength for initial temperature,

The wavelength for final temperature,

The change in wavelength is

Put the value into the formula

Hence, The shift the threshold wavelength for photoelectric emission is 2.317 nm.

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.