Part A) J. J. Thomson is best known for his discoveries about the nature of cath

Question

Part A) J. J. Thomson is best known for his discoveries about the nature of cathode rays. His other important contribution was the invention, together with one of his students, of the mass spectrometer, a device that measures the ratio of mass m to (positive) charge q of an ion.The spectrometer consists of two regions as shown in the figure.(Figure 1) In the first region an electric field accelerates the ion and in the second the ion follows a circular arc in a magnetic field. The radius of curvature of the arc can be measured and then the m/q ratio can be found.

After being accelerated to a speed of 1.72×105 m/s , the particle enters a uniform magnetic field of strength 1.00 T and travels in a circle of radius 31.0 cm (determined by observing where it hits the screen as shown in the figure). The results of this experiment allow one to find m/q.

Find the ratio m/q for this particle.

m/q = _______kg/C

Part B)Suppose a straight 1.40 mm -diameter copper wire could just "float" horizontally in air because of the force due to the Earth's magnetic field B , which is horizontal, perpendicular to the wire, and of magnitude 4.0×105 T .What current would the wire carry?Does the answer seem feasible?

Explanation / Answer

A)

here , speed of particle , u = 1.72 *10^5 m/s

magnetic field , B = 1 T

radius of loop , r = 0.31 m

radius of particle in magnetic field is

r = mv/(B*q)

0.31 = m * 1.72 *10^5/(q * 1)

m/q = 1.802 *10^-6 Kg/C

the ratio m/q for this particle is 1.802 *10^-6 Kg/C

B) please post different questions in seperate posts

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