What is a spectrometer? What is the use of a spectrometer?

12.57×10-7 Tesla is not a valid option of the answers available to choose.

A proton beam accelerated by a 100 kV potential difference enters a region where there is a 0.1 T magnetic field at right angles to the beam. i) Calculate the radius of curvature of the beam in the magnetic field region. ii) Sketch the trajectory of the proton beam and state how the velocity of the protons has been affected by the magnetic field.

3) Recall that we can analyze the nature of particles with a velocity selector and mass spectrometer. Suppose we know that the charge of the particle we're experimenting with is that of an electron but we don't know their speed and we don't know their mass. a) The velocity selector is constructed to have a magnetic field of 0.157 pointing into the paper plane and an electric field of 70N/C pointing downward. What is the speed of negatively charged particles if they don't experience any deflection? b) Suppose that those particles that are not deflected then enter a magnetic field of 37 pointing into the plane (no electric field). If we measure a diameter of the circular orbit in this magnet field of 1cm what is the mass of the particle?