Question

Express the product of 4.0 × 10-2 m and 8.1 × 102 m using the correct number of significant digits. A. 3.2 × 101 B. 3.24 × 101 C. 32.4 D. 30

Answer 1

Step-by-step explanation:

The given digits whose product has to be calculated are
`4.0 * 10^(-2)m` and
`8.1 * 10^(2)m`.

The terms
`10^(-2)` and
`10^(2)` will be cancelled out. Therefore, product of
`4.0 m * 8.1 m` is
`32.4 m^(2)`.

Hence, we can conclude that the correct number of significant digits for the product of
`4.0 * 10^(-2)`m and
`8.1 * 10^(2)`m is
`32.4 m^(2)`.

Answer 2

The correct answer is option C.

Step-by-step explanation:

Significant figures : The figures in a number which express the value of the magnitude of a quantity to a specific degree of an accuracy is known as significant digits.

`4.0* 10^(-2) m* 8.1* 10^2 m`

Using identity =
`a^m* a^n=a^(m+n)`

=
`4.0* 8.1* 10^(-2+2)`

`=32.4 m^2`

There are three significant figures in the answer. Hence, correct answer is option C.