Bright Tutorials Bright Tutorials
CBSE Class 10 Science Question 13 of 46

Solved 2023 Question Paper CBSE Class 10 Science — Question 13

Back to all questions
13
Question

Question 13

If four identical resistors, of resistance 8 ohm, are first connected in series so as to give an effective resistance Rs, and then connected in parallel so as to give an effective resistance Rp then the ratio RsRp\dfrac{R_s}{R_p} is

  1. 32
  2. 2
  3. 0.5
  4. 16
Answer

16

Reason — Four identical resistors of resistance 8 Ω are connected in series :

So, Rs = 8+8+8+8 = 32 Ω

When connected in parallel:

1Rp\dfrac{1}{R_p} = 18\dfrac{1}{8} + 18\dfrac{1}{8} + 18\dfrac{1}{8} + 18\dfrac{1}{8}

1Rp\dfrac{1}{R_p} = 1+1+1+18\dfrac{1+1+1+1}{8} = 48\dfrac{4}{8} = 12\dfrac{1}{2}

So, Rp = 2 Ω

RsRp\dfrac{R_s}{R_p} = 322\dfrac{32}{2} = 16