For this case we first write the equation of which we will use:
I (db) = 10log (l / l)
We substitute the value of l.
We have then:
l = 10 ^ 8lo
Substituting in the given equation:
I (db) = 10log ((10 ^ 8lo) / lo)
Rewriting:
I (db) = 10 * log (10 ^ 8)
I (db) = 80
Answer:
I (db) = 80
option 4