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A charged particle beam (shot horizontally) moves into a region where there is a constant magnetic field of magnitude 0.00348 T that points straight down. The charged particles in the beam move in a circular path of radius 1.17 cm. If the charged particles in the beam were accelerated through a potential difference of 110 V, determine the charge to mass ratio of the charged particles in the beam. Answer in units of C/kg.

Respuesta :

Answer:

[tex]\dfrac{q}{m}=1.32\times 10^{11}\ C/kg[/tex]

Explanation:

It is given that,

Magnetic field, B = 0.00348 T

Radius of circular path, r = 1.17 cm = 0.0117 m

If the charged particles in the beam were accelerated through a potential difference of 110 V, V = 110 V

Let q is the charge and m is the mass.

The centripetal force is balanced by the magnetic force as :

[tex]qvB=\dfrac{mv^2}{r}[/tex]

[tex]Bq=\dfrac{mv}{r}[/tex]...........(1)

Also, [tex]\dfrac{mv^2}{r}=qV[/tex]

[tex]v=\sqrt{\dfrac{2qv}{m}}[/tex]

Put the value of v in equation (1) as :

[tex]B^2q^2r^2=2qmV[/tex]

[tex]\dfrac{q}{m}=\dfrac{2V}{B^2r^2}[/tex]

[tex]\dfrac{q}{m}=\dfrac{2\times 110}{(0.00348)^2\times (0.0117)^2}[/tex]

[tex]\dfrac{q}{m}=1.32\times 10^{11}\ C/kg[/tex]

So, the charge to mass ratio of the charged particles in the beam is [tex]1.32\times 10^{11}\ C/kg[/tex]. Hence, this is the required solution.

Answer:

[tex]\frac{q}{m}=1.33\times 10^{11} \frac{C}{kg}[/tex]

Explanation:

In this question we have given,

magnetic field, [tex]B=0.00348 T[/tex]

radius of circular path, [tex]r=1.17 cm=.0117 m[/tex]

Potential difference, V=110V

let the particle of mass m be moving with velocity, v

We know that force acting on charge particle(q) moving with velocity v in a magnetic field B is given as

[tex]F=qvB[/tex]...........(1)

Similarly centripetal force on charge particle is given as,

[tex]F=\frac{mv^2}{r}[/tex]...............(2)

on comparing equation (1) and equation (2)

[tex]qvB = \frac{mv^2}{r}[/tex]

or

[tex]v = \frac{qBr}{m}[/tex]

Here kinetic energy of charge particle is due to potential difference 110V

Therefore,

Kinetic energy = Energy  due to potential difference 110V

[tex]\frac{mv^2}{2}= qV[/tex]...............(3)

put value of v ine equation 3

we got,

[tex]\frac{mr^2B^2q^2}{2m^2}=qV[/tex]

therefore,

[tex]\frac{q}{m}= \frac{2V}{r^2B^2}[/tex].............(4)

put value of V, r and B in equation 4

we got,

[tex]\frac{q}{m}= \frac{2\times 110 V}{(.0117 m)^2\times .00348^2}[/tex]

[tex]\frac{q}{m}=1.33\times 10^{11} \frac{C}{kg}[/tex]

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