The strength of a beta particle is its ability to cross the absorber to reach the detector.Now the strength of a beta particle depends upon the energy of the beta particle and thickness of the absorber.

A positively charged particle that is also a beta particle is a Positron.

The difference between a beta plus and beta minus particle is the electrical charge. The charges are equal, but opposite. The beta minus particle is an electron with a negative charge, while the beta plus particle is an anti-electron or positron with a positive charge.

negative, -1 to be precise

since a beta particle is an electron

A beta particle is an electron (or positron) with high energy and speed.