Question

To express the speed of the supersonic jet, which is 130000 m/s, in the standard form, we write it as $1.3\times {10}^a$ m/s. The value of $a$ is _______ .

• A. 4
• B. 6
• C. 7
• D. 5

Answer 1

The correct option is D 5

Given, Speed of the jet = 130000 m/s
We know, any number can be expressed as a decimal number between 1.0 and 10.0 including 1.0, and it being multiplied by a power of 10. Such form of a number is called its standard form.
$⟹130000=13\times 10000=13\times {10}^4=1.3\times {10}^5$
Therefore the standard form of 130000 is $1.3\times {10}^5$.
Hence, $a=5$.