Answer:
3 significant figures are in 400..
Explanation:
Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.
Rules for significant figures:
- Digits from 1 to 9 are always significant and have infinite number of significant figures.
- All non-zero numbers are always significant. For example: 654, 6.54 and 65.4 all have three significant figures.
- All zero’s between integers are always significant. For example: 5005, 5.005 and 50.05 all have four significant figures.
- All zero’s preceding the first integers are never significant. For example: 0.0078 has two significant figures.
- All zero’s after the decimal point are always significant. For example: 4.500, 45.00 and 450.0 all have four significant figures.
- In a non decimal number like 30 , there are 1 significant figure but number in which decimal is written after zero then all the zeros will become significant.
Given = 400.
As we can see that decimal point is present after 0 which makes the all the zeros of the number significant.
So, significant figures are in 400. is 3.
