Which of the following is the correct scientific notation for 0.00078?

• A. 78 \times 10^{-5}
• B. 7.8 \times 10^{4}
• C. 7.8 \times 10^{-4}
• D. 7.8 \times 10^{-5}

Answer: (C)

Verified step by step guidance

1. Identify the original number: 0.00078.
2. Recall that scientific notation expresses a number as \(a \times 10^{n}\), where \$1 \leq a < 10\( and \)n$ is an integer.
3. Move the decimal point in 0.00078 to the right until you get a number between 1 and 10. Count how many places you move the decimal.
4. Since moving the decimal point 4 places to the right converts 0.00078 to 7.8, the exponent \(n\) will be negative 4 because the original number is less than 1.
5. Write the number in scientific notation as \$7.8 \times 10^{-4}$.