- #1
Skalvig
- 1
- 0
- Homework Statement:
- Solve for the current
- Relevant Equations:
- U = RI
This is the solution from the book. But I only get 0,037 A. What am I doing wrong?
In my book ##\frac {5.0}{2.67}## should be greater than 1. So both your answer and the book answer are wrong!Homework Statement:: Solve for the current
Relevant Equations:: U = RI
View attachment 314307
This is the solution from the book. But I only get 0,037 A. What am I doing wrong?
##2\cdot 67##, not ##2.67##.In my book ##\frac {5.0}{2.67}## should be greater than 1. So both your answer and the book answer are wrong!
Aha. Should have gone to Specsavers (for anyone in the UK).##2\cdot 67##, not ##2.67##.
That one’s international I think.Should have gone to Specsavers (for anyone in the UK)
Also, I'm assuming that ##2## is an exact number here. Again the rule that applies is:https://en.wikipedia.org/wiki/Significant_figures#Multiplication_and_division said:the calculated result should have as many significant figures as the least number of significant figures among the measured quantities used in the calculation.
Therefore the calculated result should have 2 significant figures; which both your answer and the book's answer have.https://en.wikipedia.org/wiki/Significant_figures#Identifying_significant_figures said:
- An exact number has an infinite number of significant figures.
- If the number of apples in a bag is 4 (exact number), then this number is 4.0000... (with infinite trailing zeros to the right of the decimal point). As a result, 4 does not impact the number of significant figures or digits in the result of calculations with it.
The rule with multiplication/division:
Also, I'm assuming that ##2## is an exact number here. Again the rule that applies is:
Therefore the calculated result should have 2 significant figures; which both your answer and the book's answer have.
Somehow the book has rounded the answer to 1 significant figure (as if ##2## wasn't exact) but still added a trailing zero, which makes no sense.
I prefer your answer.
While this is likely, we simply don’t know this without knowing the original problem statement.The book is incorrect. Their answer advertises itself to be correct to two sig fig but it is not.
I don't see a reasonable scenario where the book can be correct. Please elucidate.While this is likely, we simply don’t know this without knowing the original problem statement.
I don't see a reasonable scenario where the book can be correct. Please elucidate.
Alternatively this is a middle step where some things were rounded but all decimals kept in the actual computation.
It is a stretch, but the intermediate rounding theory just barely holds water.The book’s answer seems rounded without taking the last digit away. Alternatively this is a middle step where some things were rounded but all decimals kept in the actual computation.