Question

if 10000J of energy is available to plants, how much energy is available to deer to pass it on to the lion?

Answer 1

At each trophic level about 10% of the energy of the previous trophic level is passed to the next food chain. This is known as 10% law. Now according to this law only 10% of the energy is transfer to each trophic level.

So if 10000 joules of energy is available to producer (plants) then to primary consumer (deer) only 1000 joules would be available and to the secondary consumer (Lion) 10% of the energy of the primary producer would be transfer which is 100 joules.

Note : Lion can not be primary consumer as it does not eat plants.