What is the speed of a proton that has been accelerated from rest through a potential difference of 4.0 kV? A)1.1*10⁶ m/s B)9.8 *10⁵ m/s C)8.8 * 10⁵ m/s D)1.2 *10⁶ m/s E)6.2* 10⁵ m/s

Question

Quizplus · Accepted Answer

We can use the equation $v=\sqrt{\frac{2qV}{m}}$ where $q$ is the charge of the proton, $V$ is the potential difference, and $m$ is the mass of the proton. Plugging in $q=1.602	imes 10^{-19}	ext{ C}$, $V=4000	ext{ V}$, and $m=1.673	imes 10^{-27}	ext{ kg}$, we get $v=\sqrt{\frac{2(1.602	imes 10^{-19}	ext{ C})(4000	ext{ V})}{1.673	imes 10^{-27}	ext{ kg}}}=8.8	imes 10^5	ext{ m/s}$, which is equivalent to $8.8	imes 10^7	ext{ cm/s}$ or $8.8	imes 10^{15}	ext{ \AA/s}$. Therefore, the answer is C.

What Is the Speed of a Proton That Has Been