From the given question,
There are given that exponent form is:

Now,
Multiply 500 with given form

So,

Then the reprted this answer in scientific notation.
According to scientific notation is way of representing between 1 and 10 including 1 and excluding 10 multiplied by appropriate power of 10.
Now,
In given result , we move the decimal 3 times to left side.
Since, the decimal is moved left side, we multiply by

Then,

So,
The exponent is quantity represent the power to which a given number or expression is to be raised.
Then,

Hence, the exponent is -5.