Before entering a mass spectrometer, ions pass through a velocity selector consi

Question

Before entering a mass spectrometer, ions pass through a velocity selector consisting of parallel plates separated by 1.7 mm and having a potential difference of 185 V. The magnetic field between the plates is 0.42 T. The magnetic field in the mass spectrometer is 1.2 T.

( I only need help with seconed question cuz I did the first one )

1)(a) Find the speed of the ions entering the mass spectrometer.

260504.2   m/s

2)(b) Find the difference in the diameters of the orbits of singly ionized 238U and 235U. (The mass of a 235U ion is 3.903 x 10-25 kg.)

_________mm

Explanation / Answer

Given :- mass of 235u ion = 3.903 × 10^-25 kg

Mass of 238u ion = 3.953 × 10^-25 kg

B = 1.2 T

V = 260504.2 m/s

F centripital = m (v^2/r) = F magnetic = qvB
Rearranging, r = (mv^2) / (qvB) = mv / qB

Then for 235U, r = (3.903 x 10-25)(260504.2l) / (1.6 x 10^-19)(1.2) = 5.30 x 10^-11 m   

D = 2.65 × 10^-11m

Then for 238U, r = ( 3.953 × 10-25 )*(260504.2)/ (1.6 × 10^-19)*(1.2) = 5.36 × 10^-11m

D = 2.68 × 10^-11m

Then difference in diameter is 0.03 × 10^-11m= 0.03 × 10^-8mm

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

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