A charged particle moving in a magnetic field experiences a resultant force

When does a charged particle moving in a magnetic field experience no force? .

A stationary charged particle in a magnetic field experiences a magnetic force. Is this statement true.

A charged particle placed in a uniform magnetic field experiences :

The velocity of a charged particle moving in a magnetic field perpendicular to it is

A charged particle enters a uniform magnetic field experience an upward force as indicated in the figure. What is the charge sign on this particle?