Before solving this question first we have to understand work function.
The work function of a metal is amount of minimum energy required to emit an electron from the surface barrier of metal . Whenever the metal will be exposed to radiation a part of its energy will be utilized to emit an electron while rest will provide kinetic energy to the electron.
Let f is the frequency of incident radiation and f' is the frequency corresponding to work function. Let v is the velocity of the ejected electron.
we know that velocity of an electromagnetic wave is the product of frequency and wavelength. Hence frequency f is given as-
where c is velocity of light and is the wavelength of the wave.
As per the question incident wavelength =313 nm
[as 1 nm =10^-9 m]
The wavelength corresponding to work function is 351 nm i.e
we know that hf=hf'+K.E [ h is the planck's constant whose value is 6.63×10^-34 J-s]
⇒K.E =hf-hf'
[ans]
Answer:
We can solve this by analyzing the choices and the relations between variables.
Notice that Kinetic Energy depends on the speed and the mass. Actually the Kinetic Energy is directly proportional to those variables, which means the more mass or the more speed, the more Kinetic Energy would be.
Having said that, Part I and Part II must have speed and mass as independent variable, because Kinetic Energy depends on them.
Then, in the third question, the answer is Kinetic Energy because that's the dependent variable in both cases Part I and Part II.
Just to remember, the Kinetic Energy is defined as
Where you can notice the relation between mass, speed and kinetic energy.
Therefore, the right answer are Mass (Part I), Speed (Part II) and Kinetic Energy (Part III).
Explanation:
We know: θ = ωo t + 1/2*α*t^2
so, α = 2*(θ - ωo t ) / t^2
Given: angular velocity = 96.0 rad/sectime = 7 secangular distance travelled = 28 rev
We know, In one revolution it completes 360 degrees = 6.28319 radangular distance traveled = 28 rev * 6.28319 rad
So, angular acceleration = 2*(28*6.28 - 96*7) / 7^2 = -20.25 rad/sec^2
Explanation:
speed of an object is the magnitude of the rate of change of its position with time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity.
Answer:
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