Question

Which of the following have same number of significant figures?
(A) 0.0025
(B) 0.0430
(C) 5005
(D) 500.0
(E) 2.003

• A. A & B only
• B. B, C & D only
• C. C, D & E only
• D. A, C & D only

Hint:

Always remember that trailing zeros are only significant if there is an explicit decimal point in the number.
For example, 500 has 1 significant figure, but 500.0 has 4 significant figures.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks us to identify which of the given numerical values have the same number of significant figures.

Step 2: Key Formula or Approach:
We apply the standard rules for counting significant figures:
1. All non-zero digits are significant.
2. Zeros between non-zero digits are significant.
3. Leading zeros are not significant.
4. Trailing zeros to the right of the decimal point are significant.

Step 3: Detailed Explanation:

• Let us analyze each given option:

• (A) 0.0025:
The leading zeros are not significant. Only '2' and '5' are significant.
Number of significant figures = 2.

• (B) 0.0430:
The leading zeros (0.0) are not significant. The non-zero digits '4' and '3' are significant, and the trailing zero '0' is significant because it is after the decimal point.
Number of significant figures = 3.

• (C) 5005:
All digits are significant because the zeros are sandwiched between non-zero digits.
Number of significant figures = 4.

• (D) 500.0:
The trailing zeros are significant because they are to the right of the decimal point.
Number of significant figures = 4.

• (E) 2.003:
The zeros are significant because they are between non-zero digits.
Number of significant figures = 4.

• Comparing the values, (C), (D), and (E) all have exactly 4 significant figures.


Step 4: Final Answer:
The correct option is (C), which states C, D & E only.