devarshi-dt-logo

Question:

Two large vertical and parallel metal plates having a separation of 1 cm are connected to a DC voltage source of potential difference X. A proton is released at rest midway between the two plates. It remains at rest in the air then X is:

1×10𕒹V

1×10𕒽V

1×10𕒻V

1×10𕒵0V

Solution:

Force on proton is equal to force due to its mass
qE=mg
qVd=mg
V=mgd/q=10⁻¹¹V