Two insulating plates are both uniformly charged in such a way that potential difference between them is (V₂ -V₁ = 20 V) (i.e., plate 2 is at higher potential). The plates are separated by d = 0.1 m and can be treated as infintely large. An electron is released from rest on the inner surface of plate 1. What is its speed when it hits plate 2 ?
(e = 1.6 x 10^-19 C, m_e = 9.11x 10^-31 kg)

Question

Infinity Learn · Accepted Answer

Given that $$V2$$ >$$V1$$ i.e., the electric field will point, from plate $$2$$ to plate $$1$$ as shown in fig. The moving electron will experience au electric force, opposite to the direction of electric field.Using work energy theorem, we $$havemev22$$−$$0=eV2$$−$$V1or$$     $$9$$⋅$$11$$×$$10$$−$$312v2=1$$⋅$$6$$×$$10$$−$$19$$×$$20$$∴ $$V=1.6$$×$$10$$−$$19$$×$$409.11$$×$$10$$−$$31$$ or  $$V=2.65$$×$$106m/s$$.

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