Magnetic Effects of Current and Magnetism — MCQ Practice

A long straight wire carries a current of $10\,\text{A}$. At what perpendicular distance from the wire will the magnetic field strength be $2 \times 10^{-5}\,\text{T}$? (Given: $\mu_0 = 4\pi \times 10^{-7}\,\text{T}\,\text{m/A}$)

An electron enters a uniform magnetic field of $0.2\,\text{T}$ with a velocity of $4 \times 10^6\,\text{m/s}$ perpendicular to the field. What is the radius of the circular path it follows? (Given: mass of electron $m_e = 9.1 \times 10^{-31}\,\text{kg}$, charge of electron $e = 1.6 \times 10^{-19}\,\text{C}$)

Two long parallel wires are placed $10\,\text{cm}$ apart. They carry currents of $5\,\text{A}$ and $10\,\text{A}$ respectively in the same direction. What is the force per unit length between them? (Given: $\mu_0 = 4\pi \times 10^{-7}\,\text{T}\,\text{m/A}$)

A circular coil of $20$ turns and radius $10\,\text{cm}$ carries a current of $0.5\,\text{A}$. What is the magnetic field at the center of the coil? (Given: $\mu_0 = 4\pi \times 10^{-7}\,\text{T}\,\text{m/A}$)

Which of the following statements is INCORRECT regarding the magnetic force on a charged particle?

A solenoid of length $50\,\text{cm}$ has $1000$ turns and carries a current of $2.5\,\text{A}$. What is the magnetic field inside the solenoid? (Given: $\mu_0 = 4\pi \times 10^{-7}\,\text{T}\,\text{m/A}$)

A galvanometer has a resistance of $50\,\Omega$ and gives a full-scale deflection for a current of $10\,\text{mA}$. How would you convert it into an ammeter to measure currents up to $5\,\text{A}$?