本题目来源于试卷: Nuclear & Quantum Physics E.2 Quantum Physics，类别为 IB物理学
[单选题]
RRed and blue light beams of equal vap3k 7 d3mnb6kowg. 0intensiti w2hag27y(xz4n ,l cbvk-rfq:es illuminate a photosensitive plate and produceah22nr kw-,4xvf: (z qbcylg7 photocurrents $I_R$ and $I_B$ respectively. The respective stopping voltages against the two photocurrents are $V_R$ and $V_B$.
Consider the following statements:
I. $I_R$>$I_B$
II. $V_R$<$V_B$
III. Photoelectrons with higher kinetic energy result in a higher current.
Which statements are correct?
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
参考答案: A
本题详细解析:
Explanation: Intensity of a beam increases with: The energy of photons (∵E=hf, each blue photon carries higher than a red photon). Number of photons delivered by the beam per second (since red photons pack less energy than the blue one, their number needs to be greater to have the same intensity as the blue beam). More photons eject more electrons, and hence the red beam causes higher photocurrent (I is true). Higher energy photons impart higher kinetic energy to photons, and thus the blue beam needs a higher stopping voltage (II is also correct). The kinetic energy of photoelectrons does not increase the photocurrent in the circuit as current is dependent on the number of electrons passing a point in a given time and not their individual speeds (III is incorrect).
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