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Answer:
c. The incident light must have at least as much energy as the electron work function
Explanation:
In photoelectric effect, electrons are emitted from a metal surface when a light ray or photon strikes it. An electron either absorbs one whole photon or it absorbs none. After absorbing a photon, an electron either leaves the surface of metal or dissipate its energy within the metal in such a short time interval that it has almost no chance to absorb a second photon. An increase in intensity of light source simply increase the number of photons and thus, the number of electrons, but the energy of electron remains same. However, increase in frequency of light increases the energy of photons and hence, the
energy of electrons too.
Therefore, the energy of photon decides whether the electron shall be emitted or not. The minimum energy required to eject an electron from the metal surface, i.e. to overcome the binding force of the nucleus is called ‘Work Function’
Hence, the correct option is:
<u>c. The incident light must have at least as much energy as the electron work function</u>
Answer:
0.9 m,386.36 Hz
Explanation:
We are given that
Speed of train,vs=32 m/s
Frequency of whistle,f0=350 Hz
We have to find the wavelength of sound and the frequency of heard by the listener in front of the locomotive.
Speed of sound=
We know that the frequency of listener
Using the formula
Wavelength,
Using the formula
Answer:
In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system.
Explanation:
Equilibrium is defined as a state of balance or a stable situation where opposing forces cancel each other out and where no changes are occurring. ... An example of equilibrium is when hot air and cold air are entering the room at the same time so that the overall temperature of the room does not change at all.
