To calculate \( 4.8 \times 10^{-3} - 9.4 \times 10^{-6} \), we need to express both numbers with the same exponent.
First, let's express \( 4.8 \times 10^{-3} \) with an exponent of \( 10^{-6} \):
\[ 4.8 \times 10^{-3} = 4.8 \times 10^{-3} \times \frac{10^3}{10^3} = 4.8 \times \frac{10^{0}}{10^{-3}} = 4.8 \times 1000 \times 10^{-6} = 4800 \times 10^{-6} \]
Now we have:
\[ 4800 \times 10^{-6} - 9.4 \times 10^{-6} \]
We can now subtract these two terms:
\[ (4800 - 9.4) \times 10^{-6} = 4790.6 \times 10^{-6} \]
Next, we convert \( 4790.6 \) into scientific notation:
\[ 4790.6 = 4.7906 \times 10^{3} \]
So, combining the exponents:
\[ 4790.6 \times 10^{-6} = 4.7906 \times 10^{3} \times 10^{-6} = 4.7906 \times 10^{-3} \]
Thus, the final answer in scientific notation is:
\[ \boxed{4.7906 \times 10^{-3}} \]