An/A ______ is used as the measure of count.

Q. An/A is used as a measure or a count .

Q. Among the following, which is used as an approximate method to measure length?

Q. Let us define, the length of a vector $a\overline{i}+b\overline{j}+c\overline{k}$ as $|a|+|b|+|c|$. This definition coincides with the usual definition of the length of a vector $a\overline{i}+b\overline{j}+c\overline{k}$ if

Q. Let us define the length of vector $a\hat{i}+b\hat{j}+c\hat{k}$, as $|a|+|b|+|c|$. This definition coincides with the usual definition of length of a vector $a\hat{i}+b\hat{j}+c\hat{k}$ if and only if

Q. Which instrument is used to measure the length of an object?