Question

The order of magnitude of $0.00701$ is given as,
$\begin{align}
  & A.-3 \\
 & B.-1 \\
 & C.2 \\
 & D.1 \\
\end{align}$

Answer 1

Hint: An order of magnitude is a method of an approximation to the logarithm of certain values in comparison to some of the universally accepted reference values. Usually the reference value is taken in order of tens. This has been interpreted as the base of the logarithm and they are indicating the magnitude of the actual value. These all may help you to solve this question.

Complete step-by-step answer:
The value mentioned in the question is given as $0.00701$.
First of all in order to determine the order of magnitude of a number, the value should be written in terms of tens of a number. So let us convert the given value in terms of tens.
We know that,
$N=a\times {{10}^{b}}$
Here the variable $b$is the order of magnitude of the given value $N$.
So the value can be written as,
$0.00701=7\times {{10}^{-3}}$
Therefore here the order of magnitude will be,
$b=-3$
This has been given as the first option. Hence the correct answer is option A.

Note: In order to take the order of magnitude, the number must always be written in the scientific notation first. Scientific notation is the way of writing a number in terms of a product of something from one to ten and the exponential part containing the power of ten. Each consecutive exponent number is found to be bigger for ten times than the previous one and negative exponents are indicative for small values of numbers or the decimals Orders of magnitude are commonly helpful in making very approximate comparisons and this will reflect a very huge difference. In the field of science especially physics, it sometimes needs only the order of magnitude for an estimation of parameters of subatomic particles.