F = 20 H m - ?

The equation F = 20H relates force (F) to magnetic field strength (H), indicating that the force is equal to 20 times the magnetic field strength.

Now, you are looking for the unknown variable "m". However, since there is no mention of "m" in the given equation, I am unable to provide a specific answer for it.

If you could provide more context or provide another equation relating "m" to the given variables, I would be happy to assist you further.