MEDRADSC 1C03 Lecture Notes - Lecture 13: Standing Wave, Centripetal Force, Central Force

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 1C03
• Professor: Blaszynski

Document Summary

Atoms the basics: s(cid:373)allest u(cid:374)it of (cid:373)atter that retai(cid:374)s the (cid:272)he(cid:373)i(cid:272)al propert(cid:455) of a(cid:374) ele(cid:373)e(cid:374)t, ele(cid:272)tri(cid:272)all(cid:455) neutral, nu(cid:272)leus => +"(cid:448)el(cid:455) (cid:272)harged; proto(cid:374)s (cid:894)+(cid:895), (cid:374)eutro(cid:374)s, ele(cid:272)tro(cid:374) (cid:272)loud => -"(cid:448)el(cid:455) (cid:272)harged (cid:894)-) L=mvr: the model states that this angular momentum (l) needs to be integer multiples of a fundamental quantity. Ln=n(h/2pi)=nh (h with line thru it) h& : planck"s constant h = 6. 626 x10-34 j s. = (cid:894)h/(cid:1006) (cid:895) = (cid:1005). (cid:1004)(cid:1009)(cid:1008) (cid:454)(cid:1005)(cid:1004)-34 j s. This is the centripetal force that keeps the electron moving in a circle: f= ke2/r2=mv2/r: multiply both sides by r, we get: ke2/r=mv2, now we can express the total energy as: etotal = mv2-ke2/r. If the angular momentum is quantized, then only certain orbital radius values are allowed. A wave that is repeatedly reflected between two boundaries forms a standing wave. Two fixed ends must have zero amplitude.