<span>(60km/hr) * (1000m/km)
km cancels with km
=60,000m/hr)
(60,000m/hr) * (1hr/3600s) = 16.67m/s</span>
Atoms from two different elements may have the same number of neutrons, but never the same number of protons
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]
Explanation:
We have,
Mass of an automobile is 1150 kg
The automobile traveling at 86 km/h and then it comes to stop.
86 km/h = 23.88 m/s
It is required to find work done by the automobile.
Concept used : Work energy theorem
Th change in kinetic energy of an object is equal to the work done by it. The work done is then given by :
Here, v = 0
or
Therefore, the work done by the automobile is .