2. The component of the external magnetic field along the central axis of a 50-turn coil of radius 5.3 cm increases from 0 T to 1.8 T in 3.3 s. (a) If the resistance of the coil is 2.8 92, what is the magnitude of the induced current in the coil? (b) What is the direction of the current if the axial component of the field points away from the viewer?

4. A long straight wire of length 0.2 m is attached to a wall by a horizontal spring with a spring constant of k = 10 N/m. (Neglect gravity.) The wire is sitting in a uniform 0.5-T magnetic field (B) that points out of the page. When a current is turned on in the wire, the spring is stretched by 1.0 cm. What are the direction and magnitude of the current in the wire? (Recall that | Fspring = kx) A. 1.0 A, up wall B. 1.0 A, down C. 100 A, up D. 100 A, down E. 400 A, up wire 5. A long straight wire is carrying a current I = 5.0 A upward as shown in the figure below. A single, circular conducting loop of wire with a radius R = 0.02 m is located near the wire such that the closest distance from the wire to the loop's edge is 0.06 m. What must be the magnitude and direction of a current flowing around the loop such that the net magnetic field at the loop's center is zero? Iv /R A. 1.67 A, cw B. 1.67 A, cew C. 0.40 A, cw D. 0.40 A, ccw E. 1.00 A, cew 0.06 m O

2. A slinky is stretched so that there is a gap of 0.95cm between each loop. The magnetic field at the center of the slinky is measured for a range of currents and a graph is plotted of B (in milli-Tesla) versus current I (in Amperes). The result is a straight line with a slope of 0.14 mT/A and an intercept of 0.024 mT. Determine the value of 4 from this result.

An object was placed in a freezer maintained at temperature -15 degrees Celsius. Assuming the system obeys Newton's Law of Cooling, show how the following is the differential equation describing the temperature T of the object at any timet when it is placed in the freezer? dT k(T + 15) %3D dt