JEE Main201815 Apr 2018Evening ShiftPhysicsMagnetic Effects of CurrentActual
A current of 1 ~A is flowing on the sides of an equilateral triangle of side 4.5 10⁻² ~m . The magnetic field at the centre of the triangle will be:
Options
- A4 10⁻⁵ ~Wb / m ^2
- BZero
- C2 10⁻⁵ ~Wb / m ^2
- D8 10⁻⁵ ~Wb / m ^2
Correct answer
A. 4 10⁻⁵ ~Wb / m ^2
Step-by-step solution
Here, side of the triangle, l=4.5 10⁻² ~m , current, I =1 ~A magnetic field at the centre of the triangle ' O ' B= ? From figure, 60^ = 3 = 1 2 d d= l 2 3 = ( 4.5 10⁻² 2 3 ) m Magnetic field, B= ₀ i 4 d ( ₁+ ₂ ) Putting value of =4 10⁻⁷ and ₁ and ₂ we will get net magenetic field =3 B=4 10⁻⁵ ~Wb / m ^2