Answer: 127.7 MHz.
- A 12.77 MHz
- B 63.87 MHz
- C 127.7 MHz
- D 637 MHz
Correct answer: C. 127.7 MHz
Explanation: Larmor frequency f = gamma x B/(2pi) where gamma_H = 2.675 x 10<sup>8</sup> rad/(T s). f = 2.675x10<sup>8</sup> x 3/(2pi) = 127.7 MHz.
Magnetic field of a bar magnet: field lines emerge from the north pole and re-enter at the south pole outside the magnet, forming continuous closed loops. Image: Geek3, CC BY-SA 3.0, via Wikimedia Commons.
Concept context
Bar magnets, Earth's magnetism, and how different materials respond to an external magnetic field - diamagnetic, paramagnetic, and ferromagnetic behaviour.