Problem 19

To convert the number $4800000$ into scientific notation, we follow the steps below:

1. Move the decimal point in $4800000$ so that it is after the first non-zero digit. In this case, we move it 6 places to the left, which gives us $4.8$.
2. Count the number of places the decimal point has been moved. This count is $6$.
3. Write the number as a product of the number obtained in step 1 and $10$ raised to the power of the count from step 2. This gives us $4.8 \times 10^{6}$.

Therefore, the number $4800000$ in scientific notation is represented as $4.8 \times 10^{6}$.

Hence, the correct answer is $\boxed{B}$.