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A beam of electrons is accelerated through a potential difference of 7.0 kV before entering a velocity selector. If the B-field of the veloc
Question
A beam of electrons is accelerated through a potential difference of 7.0 kV before entering a velocity selector. If the B-field of the velocity selector is perpendicular to the velocity and has a value of 0.04 T, what value of the E-field is required (in the magnetic field region) if the particles are to be undeflected?
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Physics
5 years
2021-08-31T12:11:51+00:00
2021-08-31T12:11:51+00:00 2 Answers
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Answers ( )
Given Information:
Potential difference = V = 7 kV
Magnetic field = B = 0.04 T
Required Information:
Electric Field = E = ?
Answer:
Electric Field = 1.98×10⁶ V/m
Step-by-step explanation:
The required Electric field can be found using
E = vB
Where v is the velocity of electron beam and B is the magnetic field
But first we need to calculate the velocity
V = E/q
E = Vq
Where V is the potential difference and q is the charge 1.60×10⁻¹⁹ C
E = 7×10³*1.60×10⁻¹⁹
E = 11.2×10⁻¹⁶ J
As we know
E = ½mv²
Where m is the mass of electron 9.11×10⁻³¹ kg
v = √2E/m
v = √2*11.2×10⁻¹⁶/9.11×10⁻³¹
v = 4.958×10⁷ m/s
Finally we can now calculate the Electric field
E = vB
E = 4.958×10⁷*0.04
E = 1.98×10⁶ V/m
Therefore, an electric field of 1.98×10⁶ V/m is required if the particles are to be undeflected.
Explanation:
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