A conducting bar rests to complete a circuit and immersed on a uniform magnetic field of B = 0.43 T. It is made of silver, has a length of 0.35 m, and diameter of 9 mm. The resistor on the circuit has 28 ohms resistance. Calculate the initial acceleration of the bar, when the resistor's resistance is decreased instantaneously to 4 ohms (due to short circuit). (Hint: you may need to calculate the maximum voltage first where the bar is in the state of equilibrium). R www B X X X XX Note: Final answer in ZERO decimal place. Use conventional current. Use pi = 3.14. Include the SI unit (s² should be written s^2). Use the following: resistivity of silver = 1.47x10-8 m density of silver = 10500 kg/m³

In the figure, ɛ = 78.1 V, Rị = 14.4 N, R2 2.91 H. Immediately after switch S is closed, what are (a) i and (b) iz? (Let currents in the indicated directions have positive values and currents in the opposite directions have negative values.) A long time later, what = 16.7 N, R3 = 39.3 N, and L = %3D

A current I = 3 A is passed through a wire. A second wire of length L = 1 m is moving with velocity v= 285.4 m s¨¹ at a distance d=1 cm perpendicular to the magnetic field generated by the first wire (see sketch below). Calculate the current in the circuit that includes the second wire and a stationary piece of wire (green in the sketch below). Take the resistance in the circuit to be 10 Q2 (Ohm). Consider the magnetic field B to be constant over the range of motion of the second wire (i.e. d » 1 ). For the permeability of vacuum take μo = 1.3×10-6 NA². Provide your answer in milliamperes (mA). Enter your answer in the box below. Wire 1 Wire 2 اد Wire loop

It is desired to construct a solenoid that will have a resistance of 5.30 Ω (at 20°C) and produce a magnetic field of 4.00 ✕ 10−2 T at its center when it carries a current of 3.40 A. The solenoid is to be constructed from copper wire having a diameter of 0.500 mm. If the radius of the solenoid is to be 1.00 cm, determine the following. (The resistivity of copper at 20°C is 1.7 ✕ 10−8 Ω · m.) (a) the number of turns of wire needed to build the solenoid (b) the length the solenoid should have, in cm.

The figure represents a moving rod of length 3 cm in a magnetic field B= 4T What is the current in the circuit represented in the figure, if the speed of the rod is 12 m/s and the resistance of the wire is 9 ohms? X X x x x R X X X X x X X X X X X X O I =122.45 mA O I =160.00 mA O I = 11.00 mA O I = 44.90 mA O I = 81.34 mA

Consider the RL direct current circuit shown. The circuit contains R = 4.0 Ω,  L = 10 mH, &  ε = 12 V. The circuit is charging. (a) Determine the time constant for the circuit? (b) What is the maximum current in the circuit? (c) What is the current one time constant (t = τ )? (d) When the current is 0.5 A, what is the strength of the magnetic field in the solenoid, with n = N/ℓ = 319x103 turns/m.  (    T×m/A)

Your physics professor is doing a demo to demonstrate Faraday’s law. He usesa 5m long wire of 10 Ohms total resistance, and he shapes it as a perfect square.Your professor places the loop in a plane perpendicular to a 2 Tesla uniformmagnetic field pointing from above into the plane of the loop. Then yourprofessor re-shaped the wire in five seconds from a square into a perfect circle.The new loop remains in the same plane.a. What is the magnitude of the average induced emf in the wire during thistime?b. Find the direction, and average magnitude of the current in the loopduring the deformation? Explain your reasoning.

How much energy is stored in a 2.60-cm-diameter, 12.0-cm-long solenoid that has 200 turns of wire and carries a current of 0.800 A?

Two long parallel conducting rails are separated by a distance d. At one end they are joined by a resistance R. A conducting bar of length d is made to slide at constant velocity v along the rails. Both the bar and the rails have negligible resistance. (a) What current flows in the circuit? (b) How much power is required to move the bar? (C) How does the power dissipated in the resistance compare with the power required to move the bar?

The Merlin rocket engines developed by SpaceX produce8.01 x 105 N of instantaneous thrust with an exhaust speed of3.05 x 103 m/s in vacuum. What mass of fuel does the engineburn each second?