Question

Which answer, to the correct number of significant figures, is closest to the true value of the expression: (9.1 x 104 )(1.1 x 10-5 )(log 10-13)(1000)g

Answer 1

Answer : The correct answer is, -13000 g

Explanation :

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

The rule apply for the multiplication and division is :

The least number of significant figures in any number of the problem determines the number of significant figures in the answer.

The given expression is:

$(9.1\times 10^4)(1.1\times 10^{-5})(\log 10^{-13})(1000)g$

As we know that,

$\log 10^{-13}=-13$

$\Rightarrow (9.1\times 10^4)(1.1\times 10^{-5})(-13)(1000)g$

$\Rightarrow -13013g$

True value means, the rounding off the number. So,

$\Rightarrow -13000g$

Therefore, the correct answer is, -13000 g