sam is comparing the half-life of two isotopes of uranium. The half-life of uranium-238 is 4.5 × 10⁹ years. The half- life of uranium-233 is 1.6 × 10⁵ years. He computed how much greater the half-life of uranium-238 is than that of uranium-233, and his calculator displayed the number 2.81E4. Which is this number in scientific notation?
A. 2.81 × 10^-⁴
B. 4 × 10^2.81
C. 2.81 × 10⁴
D. 2.81 + 10⁴
The number 2.81E4 can be written in scientific notation as 2.81 × 10⁴. Therefore, the answer is C. 2.81 × 10⁴.
To convert the number 2.81E4 to scientific notation, we need to move the decimal point to the right so that there is one non-zero digit to the left of the decimal point. The exponent of the power of 10 will be the number of places we need to move the decimal point.
In this case, we move the decimal point four places to the right, resulting in the number 28,100. So, 2.81E4 is equal to 28,100.
Now, we can express this in scientific notation by dividing 28,100 by 10,000 and multiplying it by 10^4. So, 28,100 can be written as 2.81 × 10^4.
Therefore, the correct answer is C. 2.81 × 10^4.
The number 2.81E4 is already in scientific notation.
Therefore, the answer is C. 2.81 × 10⁴.