NEET2019PhysicsMagnetic Effects of CurrentActual
Find force per unit length at P .
Options
- A10⁻⁴ ~m
- B10⁻⁴ ~N ~m ⁻¹
- C10⁻⁴ ~N ~m ⁻¹
- D0.3 ~N ~m ⁻¹
Correct answer
B. 10⁻⁴ ~N ~m ⁻¹
Step-by-step solution
Let length of wire element at P is d . Magnetic field at P , aligned & B= ₀ i 4 r +0+ ₀ i 4 r & B= ₀ 5 4 5 10⁻² 2= ₀ 200 4 & B=2 10⁻⁵ ~T & F=i B d l F d l =i B=5 2 10⁻⁵=10⁻⁴ Nm ⁻¹ aligned