Final answer:
The power of 10 when 0.00503 is written in scientific notation is -3, making it 5.03 x 10^-3.
Step-by-step explanation:
To express the number 0.00503 in scientific notation, we adjust the decimal point so that there's only one non-zero digit to the left of the decimal point. Moving the decimal point three places to the right gives us 5.03. Since we moved the decimal to the right, the power of 10 will be negative. So, 0.00503 becomes 5.03 × 10^-3 in scientific notation.