The correct answer is
Energy of electrons depends on light’s frequency, not intensity.
As per photoelectric effect, if we incident a light on metal surface it will results into emission of electron from it
if we increase the number of photons the number of electrons will increase however if we increase the frequency the number of photons will not increase
While if we increase frequency the energy of electrons will increase as
Energy of photon = Work function of metal + kinetic energy of electrons
When calcium reacts with water, the temperature changes from 18c to 39c is an exothermic reaction as energy is releasing and increasing the temperature.
<h3>What is an exothermic reaction?</h3>
Exothermic reaction are those reactions in which energy is released when a reaction completes.
An example is burning of wood.
Thus, when calcium reacts with water, the temperature changes from 18c to 39c is an exothermic reaction as energy is releasing and increasing the temperature.
Learn more about exothermic reaction
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