Amass spectrometer is used to examine the isotopes of uranium. ions in the beam emerge from the velocity selector at a speed of 3.00 3 105 m/s and enter a uniform magnetic field of 0.600 t directed perpendicularly to the velocity of the ions. what is the distance between the impact points formed on the photographic plate by singly charged ions of 235u and 238u?

  Δr =  15 m

Explanation:

Let's use Newton's second law

       F = m a

Force is magnetic

     F = q v B sin θ

Where θ = 90 since it indicates that the field is perpendicular to the velocity. The acceleration is centripetal

     a = v² / r

Let's replace

      q v B = m v² / r

      r = mv /q B  

Let's look for the mass for each isotope

     1 una = 1.660 10⁻²⁷ kg

235U        m1 = 235 uma (1,660 10⁻²⁷kg / 1 unit) = 390.1 10⁻²⁷kg

238U        m2 = 238 uma (1,660 10⁻²⁷ kg / 1 unit) = 395.1 10⁻²⁷ kf

In the exercises they indicate that ions have an unitary charge.

     q = 1.6 10⁻¹⁹ C

Let's calculate the radius for each isotope

235U

     r₁ = 390.1 10⁻²⁷ 3.00 10⁵  / (  1.6 10⁻¹⁹ 0.600)

     r₁ = 1170.3/0.96 10⁻³

     r₁ = 1.219  m

238U

     r₂ = 395.1 10⁻²⁷ 3.00 10⁵ /(1.6 10⁻¹⁹ 0.600)

     r₂ = 1185.3/0.96  10⁻³

     r₂ = 1.234 m

The distance between the two impact points is

     Δr = r₂  -r₁

     Δr = 1.234 - 1.219

     Δr =  15 m

heat the gas and measure the pressure

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.