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Câu hỏi: Cho nguồn laze phát ra chùm bức xạ có bước sóng 0,45 µm với công suất 1,2 W. Trong mỗi giây, số phôton do chùm sáng phát ra là
A. 4,42. ${{10}^{12}}$ photon/s.
B. 2,72. ${{10}^{18}}$ photon/s.
C. 2,72. ${{10}^{12}}$ photon/s.
D. 4,42. ${{10}^{18}}$ photon/s.
A. 4,42. ${{10}^{12}}$ photon/s.
B. 2,72. ${{10}^{18}}$ photon/s.
C. 2,72. ${{10}^{12}}$ photon/s.
D. 4,42. ${{10}^{18}}$ photon/s.
$\mathrm{P=N }\varepsilon\text{ =N}\mathrm{.}\dfrac{\mathrm{hc}}{\mathrm{ }\lambda}\mathrm{=N=}\dfrac{\mathrm{P }\lambda}{\mathrm{hc}}\mathrm{=}\dfrac{\mathrm{1,2}\mathrm{.0,45}\mathrm{.1}{{\mathrm{0}}^{\mathrm{-9}}}}{\mathrm{6,625}\mathrm{.1}{{\mathrm{0}}^{\mathrm{-34}}}\mathrm{.3}\mathrm{.1}{{\mathrm{0}}^{\mathrm{8}}}}\mathrm{=2,72}\mathrm{.1}{{\mathrm{0}}^{\mathrm{18}}}$
Đáp án B.