Question

What is meant by threshold energy? Why is it required?

Answer 1

Answer:

The minimum kinetic energy that the molecules must have to bring about collision of reactants, so that a reaction can take place is known as threshold energy.

Explanation:

THRESHOLD ENERGY is the sum of initial kinetic energy of reactants and the activation energy.

COLLISION of reactants takes place only if the molecules have very high energy that is kinetic energy.

Thus THRESHOLD ENERGY is very important for a reaction to take place . Threshold energy is always more than the activation energy.

Answer 2

Threshold energy is the minimum energy required to break the force of attraction between nucleus and electron is called Threshold energy.

hν=hν₀+K.E

When a beam of light of suitable wavelength is allowed to fall on a surface of the alkali metal, electrons are emitted from the surface of metal.

So threshold energy is required to eject these electrons from metal surface