A magnetic field is uniform over a flat, horizontal circular region with a radius of 1.80 mm, and the field varies with time. Inițially the field is zero and then changes to 1.50 T, pointing upward when viewed from above, perpendicular to the circular plane, in a time of 140 ms. (a) What is the average induced emf around the border of the circular region? (Enter the magnitude in pV and the direction as seen from above.) magnitude direction ---Select- v as seen from above (b) Immediately after this, in the next 55.0 ms, the magnetic field changes to a magnitude of 0.500 T, pointing downward when viewed from above. What is the average induced emf around the border of the circula region over this time period? (Enter the magnitude in uV and the direction as seen from above.) magnitude

A 185‑turn circular coil of radius 3.79 cm and negligible resistance is immersed in a uniform magnetic field that is perpendicular to the plane of the coil. The coil is connected to a 14.5 Ω resistor to create a closed circuit. During a time interval of 0.147 s, the magnetic field strength decreases uniformly from 0.537 T to zero. Find the energy ? in millijoules that is dissipated in the resistor during this time interval.

A generator uses a coil that has 370 turns and a 0.49-T magnetic field. The frequency of this generator is 60.0 Hz, and its emf has an rms value of 120 V. Assuming that each turn of the coil is a square (an approximation), determine the length of the wire from which the coil is made. B N Number Units S

An MRI technician moves his hand from a region of very low magnetic field strength into an MRI scanner's 2.10 T field with his fingers pointing in the direction of the field. His wedding ring has a diameter of 2.11 cm, and it takes 0.320 s to move it into the field.   (a)What average current is induced in the ring if its resistance is 0.0100 Ω? (Enter the magnitude in amperes.) A   (b)What average power is dissipated (in W)? W (c)   What average magnetic field is induced at the center of the ring? (Enter the magnitude in teslas.)T

(d) Calculate the magnitude of torque (in Nm) exerted by the magnetic field on the coil at the instant when the emf is a maximum. N.m (e) What is the maximum power delivered to the coil (in W)? W (f) What If? If the coil is constructed from aluminum wire, what is the cross-sectional area of the wire (in m²)? The resistivity of aluminum is 2.82 x 10-8 Q. m. m² (g) What If? Suppose the coil now has the same number of turns, dimensions, and resistance, but the maximum current that the wire can now safely carry is 4.50 A. What now is the maximum angular speed (in rad/s) with which the coil can be rotated in the same 2.20 T magnetic field? rad/s

An MRI machine needs to detect signals that oscillate at very high frequencies. It does so with an LCLC circuit containing a 15 mHmH coil. To what value should the capacitance be set to detect a 370 MHzMHz signal?

A 400 Hz alternating magnetic field produces a 0.5 V rms output from a 10-turn search coil with a diameter of 10 cm. Calculate the peak field flux density.

A rectangular loop of area A is placed in a region where the magnetic field is perpendicular to the plane of the loop. The field is allowed to vary its magnitude over time, according to the expression B = Bmax e ^ -t / Ƭ where both Bmax and Ƭ are constants. The field has for t <0 a constant value Bmax, a) Use Faraday's law to show that the induced emf in the turn is known byƐ = AB max / t * e ^ -t / Ƭ b) Obtain a numerical value for Ɛ at t = 4 s when A = 0.160 m ^ 2, Bmax = 0.350 T and Ƭ = 2 s. c) For the values ​​of A, Bmax, and Ƭ from part b), what is the maximum value of Ɛ?

In the figure below, a semicircular conductor of radius R = 0.220 m is rotated about the axis AC at a constant rate of 170 rev/min. A uniform magnetic field of magnitude 1.32 T fills the entire region below the axis and is directed out of the page. R Воли (a) Calculate the maximum value of the emf induced between the ends of the conductor. (b) What is the value of the average induced emf for each complete rotation? (c) How would your answers to parts (a) and (b) change if the magnetic field were allowed to extend a distance R above the axis of rotation? (Select all that apply.) O The value in part (a) would increase. The value in part (a) would remain the same. The value in part (a) would decrease. The value in part (b) would increase. The value in part (b) would remain the same. The value in part (b) would decrease. (d) Sketch the emf versus time when the field is as drawn in the figure. Choose File no file selected (e) Sketch the emf versus time when the field is extended as…

A circular loop with a radius of 0.21 m is rotated by 90.0° over 0.210 s in a uniform magnetic field with  B = 1.40 T.  The plane of the loop is initially perpendicular to the field and is parallel to the field after the rotation. (a) What is the average induced emf in the loop? V(b) If the rotation is then reversed, what is the average induced emf in the loop? V