The square loop, of side 10 cm, at right is located in a 0.05 T uniform magnetic field pointing directly away from you as shown. Over what time interval should the X X X X X X X magnetic field be reduced to zero in order to supply the 6 V needed to light the light bulb? (Recall the definition of magnetic flux.) X X х х X х х

The metal equilateral triangle in the figure, 20 cm on each side, is halfway into a 5.0×10−2 T magnetic field. (Figure 1) What is the magnitude of the magnetic flux through the triangle? If the magnetic field strength decreases, what is the direction of the induced current in the triangle?

An astronaut is connected to her spacecraft by a 29-m-long tether cord as she and the spacecraft orbit Earth in a circular path at a speed of 4.1  103 m/s. At one instant, the voltage measured between the ends of a wire embedded in the cord is measured to be 0.44 V. Assume the long dimension of the cord is perpendicular to the vertical component of Earth's magnetic field at that instant. (a) What is the magnitude of the vertical component of Earth's field at this location? uT(b) Does the measured voltage change as the system moves from one location to another? Explain.

Find the flux of Earth's magnetic field of magnitude 5.00 x 10-5 T through a square loop of area 40.0 cm2 for the following: (a) when the field is perpendicular to the plane of the loop T:m2 (b) when the field makes a 25.5° angle with the normal to the plane of the loop T.m2 (c) when the field makes a 90.0° angle with the normal to the plane T.m2

In an experiment designed to measure the Earth's magnetic field using the Hall effect, a copper bar 0.450 cm thick is positioned along an east-west direction. Assume n = 8.46 x 1028 electrons/m3 and the plane of the bar is rotated to be perpendicular to the direction of B. If a current of 8.00 A in the conductor results in a Hall voltage of 5.75 x 10-12 v, what is the magnitude of the Earth's magnetic field at this location? µT

If a rectangular loop of wire is placed between the two poles poles of a magnet, with the dimensions w = 0.30 m and L = 1.2 m, and carries a current | = 3.0 A ( clockwise). The magnetic field due to the magnet is uniform and of magnitude 0.90 T. The loop rotates in the magnetic field. What is the magnitude of maximum torque acting on the wire due to the magnetic field? B WC N L A D O 0.40 N · m O 0.83 N · m O 0.48 N · m O 0.97 N · m O 0.88 N · m

A circular loop of radius 12.4 cm is placed in a uniform magnetic field. (a) If the field is directed perpendicular to the plane of the loop and the magnetic flux through the loop is 8.50 ✕ 10−3 T · m2, what is the strength of the magnetic field? T(b) If the magnetic field is directed parallel to the plane of the loop, what is the magnetic flux through the loop? T · m2

The magnetic field changes from 1.2 T to 2.5 T over a fixed area of 0.05 m². Calculate the change in magnetic flux. The following equations may be useful: Ф — ВА O 0.19 Wb O 26 Wb 1 2 0.065 Wb O 74 Wb 3 4

A straight conductor of fixed length / is moving at 45 degrees to a uniform magnetic field of strength B with constant speed v. Calculate v, if B=9.7 T, 1=2.5 m and electromotive force e 5 V. Give your answer in Sl units. Answer: m/s

B (into the board) X X X X × X XX X X X X X X X X × X хххх Аххх хххх хх XX ххх ххххх eX X X X X X X X X X I = current Box is 4.5 cm by 11.5 cm. What is the angle between the current and the magnetic field? (B = 0.01 T, 0 = 29°, I = 6.08 A)