Question

A 0.301 T magnetic field in a mass spectrometer causes an isotope of sodium to move in a circular path with a radius of 0.07 m. The charge on an ion is 1.60218

Answer 1

13 2 00

Answer 2

e/m = v/Br;

e*B*r/v = m;

m = 4.23* 10^-25 kg

Answer 3

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old question

A 0.361 T magnetic field in a mass spectrometer causes an isotope of sodium to move in a circular path with a radius of 0.077m. The charge on an ion is 1.60218x10^-19C. If the ions are moving with a speed of 10500m/s, what is the isotope's mass? Answer in units of kg.   

ans

e/m = v/Br;

e*B*r/v = m;

m = 4.23* 10^-25 kg

Answer 4

The only force that can make the isotope move in a circular path is the magnetic force, which in this case must be acting perpendicular to the direction of motion at any instant, since the particle is moving in a circle with constant speed.

So equating centripetal force to the magnetic force,

(m*v*v)/r = q*v*B

where m is mass of the isotope, v is its speed, r is the radius in which it is moving, q is its charge, B is the magnetic field

which gives m = 1.596x10^(-25) kg