Free help with homework

Why join Brainly?

  • ask questions about your assignment
  • get answers with explanations
  • find similar questions

When two resistances R1 and R2 are connected in series, they consume 12W power. When they

are connected in parallel, they consume 50 W power. What is the ratio of the powers of R1 and R2?



This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
So for series connection equivalent resistance(R) = R1 + R2

for parallel connection equivalent resistance(r) =  \frac{R1*R2}{R1+R2}

so we know P = VI ⇒ P = I²R 

so for series connection 12 = V²/R   ..... {i}

for parallel connection 50 = V²/r .............. {ii}

dividing i from ii

so  \frac{50}{12}= \frac{R}{r}

⇒  \frac{25}{6}= \frac{(R1+R2)^2}{R1R2}

⇒ 6R1² + 6R2² - 13R1R2 = 0

⇒  6R1² - 9R1R2 - 4R1R2 + 6R2²= 0

⇒ 3R1(2R1 - 3R2) - 2R2(2R1 - 3R2) = 0

⇒ (2R1 - 3R2)(2R1 - 3R2) = 0

so   \frac{R1}{R2}= \frac{3}{2},\frac{2}{3}   ANSWER

1 5 1
shall i ask a question in brainly or you derive here?
ask in brainly
ok thnks
i posted
The Brain
  • The Brain
  • Helper
Not sure about the answer?
Learn more with Brainly!
Having trouble with your homework?
Get free help!
  • 80% of questions are answered in under 10 minutes
  • Answers come with explanations, so that you can learn
  • Answer quality is ensured by our experts