Ahall-effect probe to measure magnetic field strengths needs to be calibrated in a known magnetic field. although it is not easy to do, magnetic fields can be precisely measured by measuring the cyclotron frequency of protons. a testing laboratory adjusts a magnetic field until the proton's cyclotron frequency is 9.70 mhz . at this field strength, the hall voltage on the probe is 0.549 mv when the current through the probe is 0.146 ma . later, when an unknown magnetic field is measured, the hall voltage at the same current is 1.735 mv .

a) what is the strength of this magnetic field?

The value of the magnetic field is 2.01 T when Hall voltage is 1.735 mV

Explanation:

The frequency of the cyclotron can help us find the magnitude of the magnetic field, thus then we can compare the effect of increasing Hall voltage  on the probe.

Magnetic field magnitude at initial Hall voltage.

The cyclotron frequency can be written in terms of the magnetic field magnitude as follows

Solving for the magnetic field.

Thus we can replace the given information but in Standard units, also remembering that the mass of a proton is and its charge is .

So we get

We have found the initial magnetic field magnitude of 0.636 T

Magnetic field magnitude at increased Hall voltage.

The relation given by Hall voltage with the magnetic field is:

Thus if we keep the same current we can write for both cases:

Thus we can divide the equations by each other to get

Simplifying

And we can solve for

Replacing the given information we get

We get

Thus when the Hall voltage is 1.735 mV the magnetic field magnitude is 2.01 T

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.