Question

Sam is comparing the half-life of two isotopes of uranium. The half-life of Uranium-238 is 4.5×10 to the power of 9 years. The half-life of Uranium-233 is 1.6×10 to the power of 5 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. What is this number in scientific notation?
Responses

a. 2.81+10 to the power of 4
b. 2.81×10 to the power of −4
c. 4×10 to the power of 2.81
d. 2.81×10 to the power of 4

Answer 1

Do the ratio: (4.5×10^9) / (1.6×10^5) = (4.5/1.6)×10^(9−5) ≈ 2.8125×10^4, shown on the calculator as 2.81E4. That in scientific notation is

d. 2.81×10^4