讲一下第五题---**Extracted Content:**
**Part of Previous Question:**
...照射下发生光电效应, 光电子的最大初动能为 $E_k$, 已知该金属的逸出功为 $W_0$,
光常量为 $h$。 根据爱因斯坦的光电效应理论, 该单色光的频率 $v$ 为 ( )
Options for Previous Question:
A. $\frac{E_k}{h}$
B. $\frac{W_0}{h}$
C. $\frac{E_k - W_0}{h}$
D. $\frac{E_k + W_0}{h}$
**Question 5:**
Question Stem:
5. 如图所示, 两个速度大小不同的同种带电粒子 1、2, 沿水平方向从同一点垂直射入匀强磁场中, 磁场方向垂直纸面向里。当它们从磁场下边界飞出时相对入射方向的偏转角分别为 90°、60°, 则它们在磁场中运动的 ( )
Options:
A. 轨道半径之比为 1 : 2
B. 速度之比为 2 : 1
C. 时间之比为 2 : 3
D. 周期之比为 3 : 2
**Diagram Description:**
Type: Diagram illustrating trajectories of charged particles in a magnetic field.
Magnetic Field: Uniform magnetic field filling a rectangular region. Represented by multiple 'x' symbols, indicating the field direction is perpendicular to the plane of the paper and pointing inward.
Boundaries: The magnetic field region has a vertical boundary on the left (entry boundary) and a horizontal boundary at the bottom (exit boundary).
Entry: Two particles, labeled 1 and 2, enter the magnetic field from the same point on the left vertical boundary. The initial velocity direction is horizontal, indicated by an arrow labeled $v_0$. The entry is described as perpendicular to the field direction and along the horizontal direction.
Trajectories: Particle 1 follows a curved path bending downwards within the field and exits the lower horizontal boundary. Particle 2 also follows a curved path bending downwards and exits the lower horizontal boundary at a different point. These paths are arcs of circles.
Exit: Particles exit the magnetic field from the lower horizontal boundary. Arrows indicate the direction of velocity at the exit points.
Angles: The angle between the initial horizontal velocity direction and the final velocity direction at the exit point is labeled as 90° for particle 1 (exit velocity is vertical downwards) and 60° for particle 2 (exit velocity is downwards and to the right). These are the deflection angles.
Handwritten Formula: A handwritten formula "qvB = mv^2/R" is present near the trajectories.
**Other Relevant Text:**
None other than what is part of the questions and diagram labels.