28. Magnetic Fields and Forces

An electron in a cathode-ray tube is accelerated through a potential difference of 10 kV, then passes through the 2.0-cm-wide region of uniform magnetic field in FIGURE P29.60. What field strength will deflect the electron by 10°?

An antiproton (same properties as a proton except that q = -e) is moving in the combined electric and magnetic fields of FIGURE P29.61. What are the magnitude and direction of the antiproton's acceleration at this instant?

A 65-cm-diameter cyclotron uses a 500 V oscillating potential difference between the dees. What is the maximum kinetic energy of a proton if the magnetic field strength is 0.75 T?

A proton moving in a uniform magnetic field with ${\vec{v}}_1=(1.00\times {10}^6\hat{i})\text{m/s}$ experiences force ${\vec{F}}_1=(1.20\times {10}^{-16}\hat{k})\text{N}$. A second proton with ${\vec{v}}_2=(2.0\times {10}^6\hat{j})\text{m/s}$ experiences ${\vec{F}}_2=(-4.16\times {10}^{-16}\hat{k})\text{N}$ in the same field. What is $\vec{B}$? Give your answer as a magnitude and an angle measured counter-clockwise from the $+x$-axis.