[填空题]
An electron is accelerated hmdf/f39zl r6w ori1 ite0cylil x97kwr1 8/gwh*kzontally from rest in a television picture tube by a potential difference of 5500 V. It then passes between two horizontal plates 6.5 cm long and 1.3 cm apart that have a potentiax9 il0k*th l 1/w71yiwcrk8g el difference of 250 V (Fig. 17–31). At what angle $\theta$ will the electron be traveling after it passes between the plates? $^{\circ}\,$
