How do you measure effective mass?

Explanation:

1. "Effective masses" were measured using cyclotron resonance, a method in which microwave absorption of a semiconductor submerged in a magnetic field reaches a sharp peak when the microwave frequency equals the cyclotron frequency.
2. The interaction of external forces with charged particles in a magnetic field, which are alternate traveling in a circular route, is described by cyclotron resonance.
3. The magnetic field is the area around a magnetic material or a moving electric charge where the force of magnetism acts.

Therefore, one of the most successful methods for determining effective mass is to observe the behavior of carriers in the presence of a magnetic field.

Hence, this is the way to measure effective mass.