Magnetron operation — order of magnetic flux density used for electron cycloidal motion Identify the correct order of the magnetic flux density used in a typical microwave magnetron.

Introduction / Context:
A crossed-field magnetron uses a static electric field between cathode and anode cavities and a perpendicular magnetic field to force electrons into complex orbits that interact with RF fields. The magnetic field strength must be on the order of teslas to sustain proper interaction at microwave frequencies. The question asks for the correct order and unit identification.

Given Data / Assumptions:

• Magnetic flux density B is measured in Wb/m^2 (tesla).
• Typical magnetron B fields are fractions of a tesla up to about a tesla, depending on design.
• Other options list incorrect units or irrelevant quantities.

Concept / Approach:
The physically meaningful unit for magnetic flux density is Wb/m^2 (T). Orders near 0.1–1 T are common in high-power continuous or pulsed magnetrons. Values written as m/s are velocities, not flux densities, and Wb/s is a rate of change of flux, also not magnetic flux density. Therefore, 1 Wb/m^2 correctly represents the order of B used in a magnetron.

Step-by-Step Solution:

Verification / Alternative check:
Engineering references for S-band magnetrons show design B values roughly 0.1–0.3 T, consistent with the order-of-unity tesla scale used in multiple magnetron families.

Why Other Options Are Wrong:

• 1 mWb/s: time derivative of flux, not flux density.
• 10^6 m/s and 10^12 m/s: linear velocities, not magnetic flux density.

Common Pitfalls:
Confusing B (tesla) with changing flux (dΦ/dt) or with electron velocity units.

Final Answer:
1 Wb/m2