Transformer questions - primary, secondary, gaaaah

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A step-up transformer with 100 turns in the primary and 200 turns in the secondary converts a primary voltage of 100 V to a secondary voltage of 200 V. The uncertainty in the primary voltage is ±2%, which translates to ±4 V when calculating the secondary voltage. The correct secondary voltage is therefore 200 V ± 4 V, reflecting the uncertainty derived from the primary voltage. The confusion arose from the misinterpretation of how uncertainty is applied in the transformation. The final answer clarifies that the secondary voltage retains the same percentage uncertainty as the primary, resulting in a total uncertainty of ±4 V.
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Transformer questions - primary, secondary, gaaaah!

Hello, I really need help with this. Much appreciated! Thank you so much in advance for any help!

Homework Statement



A step-up transformer has exactly 100 turns in the primary and exactly 200 turns in the secondary. If the voltage in the primary is 100 V ± 2 %, what is the voltage in the secondary?

a. 200 V ± 4 V
b. 200 V ± 4 %
c. none of the other answers
d. 100 V ± 4 %
e. 200 V ± 2 V

Homework Equations



Vs/Vp=Ns/Np

The Attempt at a Solution



OK now here, I know the voltage should be 200V. But the uncertainty ... ? I really don't know where to even begin with that. I chose answer b. 200 V ± 4 %, and it was wrong.
 
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Thank you!
 


There is no more uncertainty introduced in the secondary voltage, so it is still +/- 2%. To trick you, they omitted this selection and instead put the real value of 2% which is just 2% of 200 (4 volts)
 

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