2.4×108 m/s2.4 \times 10^{8} \mathrm{~m} / \mathrm{s}2.4×108 m/s
2.4×10−9 m/s2.4 \times 10^{-9} \mathrm{~m} / \mathrm{s}2.4×10−9 m/s
2.6×108 m/s2.6 \times 10^{8} \mathrm{~m} / \mathrm{s}2.6×108 m/s
2.6×109 m/s2.6 \times 10^{9} \mathrm{~m} / \mathrm{s}2.6×109 m/s