Question

In Bainbridge mass spectrograph a potential difference of 1000 V is applied between two plates distant 1 cm apart and magnetic field in B = 1T. The velocity of undeflected positive ions in m/s from the velocity selector is

• A. $10^{7}m/ ⥂ s$
• B. $10^{4}m/ ⥂ s$
• C. $10^{5}m/ ⥂ s$
• D. $10^{2}m/ ⥂ s$

Answer 1

Answer: (C)

$10^{5}m/ ⥂ s$

Answer 2

By using $v = \frac{E}{B}$; where $E = \frac{V}{d} = \frac{1000}{1 \times 10^{- 2}} = 10^{5}V/m$

⇒ $v = \frac{10^{5}}{1} = 10^{5}m/ ⥂ s$