Chapter 4 - Polynomials - 4.2 Negative Exponents and Scientific Notations - 4.2 Exercise Set - Page 245: 112

$2.24\times10^{-7}$

Using the laws of exponents and the concepts of scientific notation, the given expression, $ \dfrac{5.6\times10^{-2}}{2.5\times10^{5}} $, simplifies to \begin{array}{l} (5.6\div2.5)\times10^{-2-5} \\\\= 2.24\times10^{-7} .\end{array}