3. If an electron starts from rest and passes through a potential difference V,

Question

3. If an electron starts from rest and passes through a potential difference V, then it gains energy in the amount of edv. Relate this potential energy to the final kinetic energy of the electron (that is, write an equation, eV-...). 4. From this expression (#3), how is the speed of an electron related to the potential difference that it passed through? That is, electron speed-ve-? Magnetic Fields -To Bend the Path of the Electrons: Running current through large coils of wire can create nice, uniform magnetic fields. The magnetic field Bcoils due to two identical, specially placed coils is dependent on the number of

Explanation / Answer

3. enegy of electron after passing through a potential difference dV = edV ( where e is charge of electron)
now, KE of an object of mass m is KE = 0.5mv^2 ( where v is velocity of electron)
so from conservation of energy
e*dV = 0.5mv^2
4. e*dV = 0.5mv^2
2e*dV/m = v^2
v = sqroot(2*e*dV/m)
5. force on electron in magentic fieldf B is qvB ( v is velocity of electron, e is charge on it)
but centripital force = mv^2/R
now as centripital force will balance the magnetic force on an electron moving in orbits
so, mv^2/R = evB
6. mv^2/R = evB
v = ReB/m
7. so from 4 and 6
sqroot(2*edV/m) = ReB/m
2*e*dV/m = R^2*e^2*B^2/m^2
m = e*R^2*B^2/2dV

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.