1981 年

物理 · 共 23 題 · 點擊選項即時核對答案

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21.

Which of the following statements concerning the generator shown in the figure is/are correct ?

(1)The direction of the current through the load reverses periodically.

(2)The maximum magnitude of the current depends on the speed of rotation of the coil.

(3)The maximum magnitude of the current depends on the resistance of the load.

22.

Which of the following represents an alpha decay ?

(1)

{}^{238}_{92}\mathrm{U}\to{}^{234}_{90}\mathrm{Th}

(2)

{}^{215}_{85}\mathrm{At}\to{}^{211}_{83}\mathrm{Bi}

(3)

{}^{210}_{81}\mathrm{Tl}\to{}^{210}_{82}\mathrm{Pb}

23.

If the three kinds of radiations $\alpha$ , $\beta$ and $\gamma$ are arranged in ascending order of their ionization power, their order is