Grade 12Electric Current

A uniform wire of resistance 4 ohm is bent into a circle of radius r. A specimen of the same wire is connected along the diameter of the circle. What is the eq resistance?

Surabhi

9 Years agoGrade 12

3 Answers

Umakant biswal

9 Years ago

@ surabhi
i think the data given is insuficient to calculate the equivalent resistance .
its not mentioned that the speciman wire have resistance or not .
so, i am assuming it to be present of 4 ohm of resister .
if so, thenit will be parallel combination of two resisters of4 ohm each /.
so,, acc to the formula
1/ R (EQUI ) = 1/R1 + 1/R2
SO, 1/R = 1/4+1/4
1/R= 2/4 = ½
so, r = 2 ohm
HOPE U ARE CLEARS NOW
IF ANSWER ISGIVEN SOMETHING DIFFRENT THEN LETME KNOW
ALL THE BEST ..

Raman Mishra

Approved Tutor Answer9 Years ago

Let the resistance per unit length be $\lambda$ . Then,

$\lambda$ = 4/ $2\pi r$

=> resistance of the specimen wire connected along the diameter is:

$R = \lambda \times 2r = \frac{4}{\pi } \Omega$

Now after the specimen wire is connected along the diameter, three resistance come in parallel:

$2 \Omega$ (resistance of one half of the circumference), $2 \Omega$ (resistance of the other half of the circumference) and R(resistance of the diameter). Solving, we get:

${\color{DarkRed}R_{eq} = \frac{4}{4+\pi } \Omega }$

Hope you understood dear Surabhi.

RANJEET KUMAR

9 Years ago

dear umakant bro..u do not have basic understanding of english neither you know physics well. please do not mislead students if you do not know the answer.