Answer:
Speed = 575 m/s
Mechanical energy is conserved in electrostatic, magnetic and gravitational forces.
Explanation:
Given :
Potential difference, U = [tex]$-3.45 \times 10^{-3} \ V$[/tex]
Mass of the alpha particle, [tex]$m_{\alpha} = 6.68 \times 10^{-27} \ kg$[/tex]
Charge of the alpha particle is, [tex]$q_{\alpha} = 3.20 \times 10^{-19} \ C$[/tex]
So the potential difference for the alpha particle when it is accelerated through the potential difference is
[tex]$U=\Delta Vq_{\alpha}$[/tex]
And the kinetic energy gained by the alpha particle is
[tex]$K.E. =\frac{1}{2}m_{\alpha}v_{\alpha}^2 $[/tex]
From the law of conservation of energy, we get
[tex]$K.E. = U$[/tex]
[tex]$\frac{1}{2}m_{\alpha}v_{\alpha}^2 = \Delta V q_{\alpha}$[/tex]
[tex]$v_{\alpha} = \sqrt{\frac{2 \Delta V q_{\alpha}}{m_{\alpha}}}$[/tex]
[tex]$v_{\alpha} = \sqrt{\frac{2(3.45 \times 10^{-3 })(3.2 \times 10^{-19})}{6.68 \times 10^{-27}}}$[/tex]
[tex]$v_{\alpha} \approx 575 \ m/s$[/tex]
The mechanical energy is conserved in the presence of the following conservative forces :
-- electrostatic forces
-- magnetic forces
-- gravitational forces