Question 673: Electrostats & Capacitance

Question

Two insulating plates are both uniformly charged in such a way that the potential difference between them is $${V_2} - {V_1} = 20\,V.$$ (i.e., plate $$2$$ is at a higher potential). The plates are separated by $$d=0.1$$ $$m$$ and can be treated as infinitely large. An electron is released from rest on the inner surface of plate $$1.$$ What is its speed when it hits plate $$2$$? 
$$\left( {e = 1.6 	imes {{10}^{ - 19}}\,C,\,\,{m_e} = 9.11 	imes {{10}^{ - 31}}\,kg} ight)$$

Accepted Answer

$$eV = {1 \over 2}m{v^2}$$
$$ \Rightarrow v = \sqrt {{{2ev} \over m}}  = \sqrt {{{2 	imes 1.6 	imes {{10}^{ - 19}} 	imes 20} \over {9.31 	imes {{10}^{ - 31}}}}} $$
$$ = 2.65 	imes {10^6}\,m/s$$

Answer

$$2.65 	imes {10^6}\,m/s$$

Answer

$$7.02 	imes {10^{12}}\,m/s$$

Answer

$$1.87 	imes {10^6}\,m/s$$

Answer

$$32 	imes {10^{ - 19}}\,m/s$$

Electrostats & Capacitance

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