Answer:
Work done is equal to 125.44 J
Explanation:
We have given mass of the student m = 80 kg
Distance moved d = 4 m
Acceleration due to gravity 
Coefficient of kinetic friction 
So normal force exerted by student 
We know that work done is equal to multiplication of force and distance
So work done 
THAT LINK IS A VIRUS NEVER GO TO A LINK and if you go to “goggle” you should see a camera icon and take a picture of the question and get the answer there
Answer:
Decrease the slit separation, increase the distance of the screen from the slits, and increase the wavelength.
Explanation:
The distance
from the central band to the first bright band is given by

where
is the wavelength of light (or any particle),
is the distance to the screen, and
is the slit separation.
From this equation we see that, by increasing the wavelength
, increasing the distance from the screen
, and decreasing the slit separation
, we increase the distance between the first bright band and the central band.
Therefore, the 2nd choice "<em>Decrease the slit separation, increase the distance of the screen from the slits, and increase the wavelength.</em>" is correct.
To solve this problem it is necessary to apply an energy balance equation in each of the states to assess what their respective relationship is.
By definition the energy balance is simply given by the change between the two states:

Our states are given by



In this way the energy balance for the states would be given by,



Therefore the states of energy would be
Lowest : 0.9eV
Middle :7.5eV
Highest: 8.4eV