Question

Assertion :The number 1.202 has four significant figures and the number 0.0024 has two significant figures. Reason: All the non zero digits are significant.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Assertion is correct

The number of significant figures in $1.202$ is four and the number of significant figures in $0.0024$ is two.

The following rules are used to find the number of significant figures.

• All non zero digits are significant.
• All zero occurring between two non zero digits are significant.
• If the number is less then one, the zero on the right side of the decimal point and to the left of the first non - zero digits are not significant

So assertion is correct by using the following rules. Also, reason is correct, since it is one of the rules to find the number of significant figures.

But reason is not the correct explanation of the assertion, because reason does not contain the second and third rules given above.

Hence, option $\left(B\right)$ is correct