Exams › NEET › Physics

At what distance from a long straight wire carrying a current of 12 A will the magnetic field be equal to 3 × 10⁻⁵ Wb/m²?

1. 8 × 10⁻² m
2. 12 × 10⁻² m
3. 18 × 10⁻² m
4. 24 × 10⁻² m

Correct answer: 8 × 10⁻² m

Solution

The magnetic field due to a long straight wire is given by B = μ₀I / (2πr). Substituting B = 3 × 10⁻⁵ Wb/m², I = 12 A, and μ₀ = 4π × 10⁻⁷ T·m/A, solving for r gives r = 8 × 10⁻² m.

Related NEET Physics questions

• An alternating electric field, of frequency ν, is applied across the dees (radius = R) of a cyclotron that is being used to accelerate protons (mass = m). The operating magnetic field (B) used in the cyclotron and the kinetic energy (K) of the proton beam, produced by it, are given by:
• A proton carrying 1 MeV kinetic energy is moving in a circular path of radius R in uniform magnetic field. What should be the energy of an α-particle to describe a circle of same radius in the same field?
• A positively charged particle moving due east enters a region of uniform magnetic field directed vertically upwards. The particle will
• An electron enters a region where magnetic field (\( \vec{B} \)) and electric field (\( \vec{E} \)) are mutually perpendicular, then
• A \( 10 \, \text{eV} \) electron is circulating in a plane at right angles to a uniform field at magnetic induction \( 10^{-4} \, \text{Wb/m}^2 \) (\( = 1.0 \, \text{gauss} \)). The orbital radius of the electron is
• A uniform magnetic field acts at right angles to the direction of motion of an electron. As a result, the electron moves in a circular path of radius \( 2 \, \text{cm} \). If the speed of electron is doubled, then the radius of the circular path will be

⚔️ Practice NEET Physics free + battle 1v1 →