A rectangular loop of wire with length 0.3 m and height 0.1 m is halfway inside a region of uniform magnetic field of 0.65 T as shown below. The total resistance of the loop is 0.2 . Calculate the force required to pull the loop from the field at a constant velocity of 0.3 m/s. Neglect gravity.

A 150-g ball containing 4.00 x 10^8 excess electrons is dropped into a 125-m vertical shaft.  At the bottom of the shaft, the ball suddenly enters a uniform magnetic field that has magnitude 0.250 T and direction from east to west.  Ignoring air resistance, find the magnitude of the force that this magnetic field exerts on the ball just as it enters the field.

A magnetic field of 37.2 T has been achieved at the MIT Francis Bitter Magnet Laboratory. Find the current needed to achieve such a field near the center of a solenoid with radius 2.40 cm, length 32.0 cm, and 40,000 turns.

A circular loop of radius 10 cm carries a current of 2 A. Calculate the magnetic field at the center of the loop.

A conducting rod spans a gap of length L = 0.085 m and acts as the fourth side of a rectangular conducting loop, as shown in the figure. A constant magnetic field B = 0.55 T pointing into the paper is in the region. The rod is moving under an external force with an acceleration a = At?, where A = 4,5 m/s*. The resistance in the wvire is R = 145 Q. L = 0.085 m B = 0.55 T A = 4,5 m/s R= 145 N B X X R V X X Express the magnitude of the magnetic flux going through the loop, , in terms of B, x and L. Express the speed of the rod, v, in terms of A and t. Assume v = 0 at t = 0. Express the position of the rod, x, in terms of 4 and t. Assume x = 0 at 1 = 0. Express the derivative of the magnetic flux, do/dt, in terms of B, 4, L and t. do/dt = Express the magnitude of the emf induced in the loop, ɛ, in terms of B, L, A and t. Express the current induced in the loop, I, in terms of ɛ and R. Calculate the numerical value of I at t = 2s in A. I(t=2s) = www

The figure below shows a piece of insulated wire formed into the shape of a figure eight. You may consider the two loops of the figure eight to be circles, where the upper loop's radius is 3.00 cm and the lower loop's radius is 8.00 cm. The wire has a uniform resistance per unit length of 9.00 Ω/m. The wire lies in a plane that is perpendicular to a uniform magnetic field directed into the page, the magnitude of which is increasing at a constant rate of 1.70 T/s. What is the magnitude of the induced current in the wire (in A)?

What is the direction of the magnetic force on the wire?  (Give the angle from the positive x-axis, negative if the angle is below the positive x-axis.)  (B = 0.029 T, θ = 37°, I = 5.94 A)

Find the magnitude of the torque on a circular loop in a uniform magnetic field of 0.021 T. The radius of the loop is 2.0 cm, the current is 13.5 A, and the angle between the magnetic field and a normal to the loop is 90°. Express your answer with the appropriate units. HA ? T = Value Units

A wire has a length of 6.68 × 10-2 m and is used to make a circular coil of one turn. There is a current of 8.92 A in the wire. In the presence of a 2.06-T magnetic field, what is the maximum torque that this coil can experience?

A piece of copper wire has a resistance per unit length of 5.12 × 10-3/m. The wire is wound into a thin, flat coil of many turns that has a radius of 0.149 m. The ends of the wire are connected to a 12.0-V battery. Find the magnetic field strength at the center of the coil.