If grass have 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000 joule of energy and deer gets 10 percent of it...

The given numerical is an example of ten percent law, according to which, only about 10% of the energy is transferred from one trophic level to the next. Here, the grass have 10^84 J of energy. The next trophic level, deer, get only 10% of the energy, or 10^83 J. Similarly, only 10% of the energy is transferred to the next trophic level. That is, the wolf will get only about 10^82 J of energy....

The given numerical is an example of ten percent law, according to which, only about 10% of the energy is transferred from one trophic level to the next. Here, the grass have 10^84 J of energy. The next trophic level, deer, get only 10% of the energy, or 10^83 J. Similarly, only 10% of the energy is transferred to the next trophic level. That is, the wolf will get only about 10^82 J of energy. Using the same principle, the lion (the highest trophic level and the topmost consumer) will get only 10% from the previous tropic level (the wolf) and hence, a lion will only get 10^81 J of energy from eating a wolf. Thus, in moving 3 tropic levels, from grass to lion, only 1000th part of the original energy is transferred. 

Some examples of biomagnification (or concentration of material in a food chain as we move up the trophic levels), include the biomagnification of pesticides, such as DDT along the food chain. Many other chemicals (such as PCBs, VC, etc.) and toxic metals (such as mercury and arsenic, etc.), also biomagnify along the food chain.

Hope this helps.