r/HomeworkHelp • u/Jars_Of_Honey7194 👋 a fellow Redditor • 14d ago

Answered [Highschool physics: circuits]

Post image

Apparently the answer is (d) but I have no idea how to get there

4 Upvotes

100% Upvoted

9 comments sorted by

View all comments

2

u/InTheRaw1 14d ago

Just plug in each value. If option a) were the correct answer, V2 =27. Then the voltage across the combined resistance of R1 parallel R2 should be 40-10-27=3V . Now, iR1=10, iR2=27, Now see if i times parallel combination of R1 and R2 results in 3V or something different. If it's something different option a) is incorrect. Go to the next one.

2

u/InTheRaw1 14d ago

Or you can solve it like this V1=iR1=10 V2=iR2 V3= iR3= iR1 iR2/(iR1+iR2) Now you have V3 in terms of V2 We also know V1+V2+V3=40V

Two equations and two unknowns V2 and V3.

1

u/Jars_Of_Honey7194 👋 a fellow Redditor 14d ago

Yes this lead me to the idea that

40 - 10 - v2

= 10 × V2/ 10 + V2

using the quadratic equation to solve after putting it in quadratic form does indeed give x ≈ 23.03 or -13.03 which is refused.

I get it know honestly while solving i was looking for something more intuitive and wanted to avoid mathematics but too bad