How many significant figures are there in a) 0.049300 & b) 4.200*10^5. Please help me
http://www.chemteam.info/SigFigs/SigFigs.html
To determine the number of significant figures in a given number, we need to follow these rules:
1. Non-zero digits are always significant.
2. Any zeros between non-zero digits are significant.
3. Leading zeros (zeros to the left of the first non-zero digit) are not significant.
4. Trailing zeros (zeros to the right of the last non-zero digit) can be significant, depending on whether they appear to indicate precision.
Let's apply these rules to each given number:
a) 0.049300:
- There are two non-zero digits: 4 and 9, so they are significant.
- The zeros between them (0 and 0) are also significant.
- The leading zero (before 4) is not significant.
- The trailing zeros (after the last non-zero digit) are significant since they appear to indicate precision.
Therefore, there are six significant figures in 0.049300.
b) 4.200 * 10^5:
This number is written in scientific notation, where the coefficient (4.200) and the power of 10 (5) need to be considered separately.
- The coefficient, 4.200, has four significant figures. The non-zero digits 4, 2, and 0 are significant, and the trailing zero is also significant because it appears to indicate precision.
- The power of 10, 5, does not have any significant figures as it denotes magnitude or scale.
Therefore, the number 4.200 * 10^5 has four significant figures.