Question

The number of significant figures in $ 0.050 $ is:
(A) $ 1 $
(B) $ 2 $
(C) $ 3 $
(D) $ 4 $

Answer 1

Hint: Significant figures are the numbers of a measurement which carries meaningful importance to the measurement. There are different rules for finding the number of significant figures in the measurement.

Complete step-by-step answer
First we start with the definition of significant figures:
Significant figures: Significant figures are the numbers of a measurement which carries meaningful importance to the measurement.
There are many rules to follow while finding the number of significant figures. So, we now talk about the rules of significant figures:
(a) Non-zeroes numbers are always significant.
(b) The zeroes in between two non-zero digits are significant.
(c) The trailing zeros in a number after the decimal are significant.
(d) The trailing zeros in a whole number not having decimal are not significant.
(e) The trailing zero before the number is always non-significant.
(f) If there is a number of the form $ 3.2 \times {10^5} $ , then only $ 3,2 $ are the significant figures that means the power terms are non-significant.
So, from the above rules we can find out the significant figure of $ 0.050 $
This measurement $ 0.050 $ is having one zero before the decimal which is not significant. Also, the second zero is not significant because the zero is before the measurement. The last zero is significant because the digit is after decimal. $ 5 $ is always significant because it is a non-zero digit. Hence, there are two significant figures in the $ 0.050 $ .
Hence, the correct option is (B) $ 2 $ .

Note:
The zeroes present in the measurement are the one which needs consideration. The measurement having a whole number the trailing zeros after the non-zero number are non-significant, like $ 1000 $ has only $ 1 $ significant figure because the last three zeroes are non-significant.