The wavelength of the light beam required to turn back all the ejected electrons is 497 nm which is option (b).
- Work function is a material property defined as the minimum amount of energy required to infinitely remove electrons from the surface of a particular solid.
- The potential difference required to support all emitted electrons is called the stopping potential which is given by
.....(1) - where
is the stopping potential and e is the charge of the electron given by
.
It is given that work function (Ф) of monochromatic light is 2.50 eV.
Einstein photoelectric equation is given by:
....(2)
where K.E(max) is the maximum kinetic energy.
Substituting (1) into (2) , we get

As we know that
....(3)
where Speed of light,
and Planck's constant , 
From equation (3) , we get

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The correct answer is the reverse wave I took the test
Answer:
The actual angle is 30°
Explanation:
<h2>Equation of projectile:</h2><h2>y axis:</h2>

the velocity is Zero when the projectile reach in the maximum altitude:

When the time is vo/g the projectile are in the middle of the range.
<h2>x axis:</h2>

R=Range


**sin(2A)=2sin(A)cos(A)
<h2>The maximum range occurs when A=45°
(because sin(90°)=1)</h2><h2>The actual range R'=(2/√3)R:</h2>
Let B the actual angle of projectile

2B=60°
B=30°
Answer:
Explanation:
Kinetic energy is energy that an object has because of its motion. The Kinetic Molecular Theory explains the forces between molecules and the energy that they possess. This theory is based on three theories about matter. Matter is composed of small particles (atoms, molecules, and ions).
As we know that range of the projectile motion is given by

here we know that range will be same for two different angles
so here we can say the two angle must be complementary angles
so the two angles must be

so it is given that one of the projection angle is 75 degree
so other angle for same range must be 90 - 75 = 15 degree
so other projection angle must be 15 degree