Single Choice

In the below figure, an electron of mass m, charge -e, and low (negligible) speed enters the region between two plates of potential difference V and plate separation d, initially headed directly towards the top plate. A uniform magnetic filed of magnitude B is normal to the plane of the figure.Find the minimum value of B such that the electron will not strike the top plate.

A$$\sqrt{\dfrac{2mV}{ed^2}}$$
Correct Answer
B$$\sqrt{\dfrac{mV}{2ed^2}}$$
C$$\sqrt{\dfrac{mV}{ed^2}}$$
D$$2\sqrt{\dfrac{mV}{ed^2}}$$

Solution

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