(Solved): answer5 1. (10 points) A current produce a magnetic field of magnitude 5T at distance 0.03m from ...

1. (10 points) A current produce a magnetic field of magnitude $5\mu \mathrm{T}$ at distance $0.03\mathrm{m}$ from a long, straight wire. What is the distance from the wire with this current where the magnitude of the magnetic field is $2\mu \mathrm{T}$ ? 2. (10 points) An electron is accelerated through $2400\mathrm{V}$ from rest and then enters a region where is a uniform 1.7 T magnetic field perpendicularly to it. What is the magnitude or magnetic force on the electron and the radius of the path? 3. (10 points) Flexible circular loop shown in $\mathrm{Fig}$. $I$ has a radius,$-5\mathrm{cm}$ and is in a magnetic field of strength $0.2\mathrm{T}$ which is perpendicular to the plane. During the time $0.5\mathrm{s}$ the loop is grasped at points A and B and stretched until its area is nearly zero. Find the average induced emf in the loop during that time and the current through the loop if its resistance is $2\Omega$. 4. ( 10 points). Find the direction of the force on a positive charge for each diagram shown in Fig. 2, where $\mathrm{v}$ is the velocity of the charge and $\mathrm{B}$ is the direction of the magnetic field. ( $\otimes$ means the vector points inward, $O$ means it points outward, toward you.) 5. (10 points) $\mathrm{A}$ conducting rod $\mathrm{AB}$ (Fig. 3) sliding with constant speed $\mathrm{v}=2\mathrm{m}/\mathrm{s}$ on conducting rails in a uniform magnetic field with $B=0.15\mathrm{T}$. The magnetic field is directed into the page as shown in Figure 3 . The rod has a length $L-0.5\mathrm{m}$ and resistance $3\Omega$. What is the current in the rod. Neglect a resistance of the rail.