A radioactive source emits a mixture of three types of radiation: PPP, QQQ, and RRR. The emissions enter a region of uniform magnetic field directed into the page, as shown in the diagram below.
Which of the following options correctly identifies emissions PPP, QQQ, and RRR, and lists them in order of decreasing ionising power (from highest to lowest)?
P=αP = \alphaP=α, Q=γQ = \gammaQ=γ, R=β−R = \beta^-R=β−; decreasing ionising power: P→R→QP \rightarrow R \rightarrow QP→R→Q
P=β−P = \beta^-P=β−, Q=γQ = \gammaQ=γ, R=αR = \alphaR=α; decreasing ionising power: R→P→QR \rightarrow P \rightarrow QR→P→Q
P=αP = \alphaP=α, Q=γQ = \gammaQ=γ, R=β−R = \beta^-R=β−; decreasing ionising power: Q→R→PQ \rightarrow R \rightarrow PQ→R→P
P=β−P = \beta^-P=β−, Q=γQ = \gammaQ=γ, R=αR = \alphaR=α; decreasing ionising power: P→R→QP \rightarrow R \rightarrow QP→R→Q