Question

A uniform current carrying cylindrical wire carries current $I$ having radius 'a'. Magnetic field with distance x varies with relation given:

• A. B ∝ x, for x < a
  B ∝$\frac{1}{x}$, for x > a
• B. B ∝ x, for x < a
  B is constant, for x > a
• C. B is constant, for x < a
  B ∝$\frac{1}{x}$, for x > a
• D. B ∝$\frac{1}{x}$, for x < a
  B ∝ x, for x > a

Answer 1

Answer: (A)

B ∝ x, for x < a
B ∝$\frac{1}{x}$, for x > a

Answer 2

B is directly proportional to ‘x’, for when the ‘x’ is lesser than ‘a’
The B is inversely proportional to ‘x’, for when the ‘x’ is greater than ‘a’.

So, the correct option is (A)