AIIMS 2007
- Exam
- AIIMS
- Year
- 2007
- Subject
- Physics
- Chapter
- Magnetic Effects of Current
AIIMS 2007 · Physics · Magnetic Effects of Current
What is the magnetic field at a distance R from a coil of radius r...
What is the magnetic field at a distance from a coil of radius carrying current ?
Options
- A(\frac{\mu_0 I R^2}{2\left(R^2+r^2\right)^{\frac{3}{2}}})
- B(\frac{\mu_0 I r^2}{2\left(R^2+r^2\right)^{\frac{3}{2}}})
- C(\frac{\mu_0 I}{2 r})
- D(\frac{\mu_0 I}{2 R})
Correct answer
B. (\frac{\mu_0 I r^2}{2\left(R^2+r^2\right)^{\frac{3}{2}}})
Step-by-step solution
A coil of radius carrying current , magnetic field at a point at a distance from the centre of the coil is given by
(B=\frac{\mu_0 I r^2}{2\left[R^2+r^2\right]^{3 / 2}})
At the centre of a coil,
(\therefore \quad B=\frac{\mu_0 I r^2}{2 r^3}=\frac{\mu_0 I}{2 r})