2. An electron moves in a straight line at a constant speed of 2.5x10 m/s in a u
ID: 1789379 • Letter: 2
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2. An electron moves in a straight line at a constant speed of 2.5x10 m/s in a uniform electric field of strength 450 V/m. If the electron is moving along the +x axis and the electric field points along the ty axis, what is the magnitude and direction of the magnetic field? If an "He nucleus (2 protons, 2 neutrons) starts with the same exact velocity (speed and direction) as the electron, what path will it follow? (B-1.80x10 T, along +z-axis, same path) 3. Two long wires cross each other at the origin of the x-y plane. The wire along the x-axis has a current in the negative x direction of 4.50 A. The wire along the y-axis has a current in the positive y direction of 1.75 A. What is the direction and magnitude of the magnetic field at (3.00 2.50) cm? At (-3.00, -2.50) cm? 2.43x10T, 4.77x10T along +z 4. A long straight wire is along the y-axis of the x-y plane and has a 3.50 A current flowing in the positive y direction. The nearest edge of a rectangular wire "loop" is 7.00 cm to the right. The loop is 10.0 cm in the y direction and 3.00 cm in the x-direction. If a 2.00 A current flow clockwise in this loop, what is the total magnetic force (magnitude and direction) on this loop from the long straight wire? (6.00x10'N, towards the wire) 5. The area of a 100 turn coil is.0500m2. There is a upward magnetic field of strength 0.200T perpendicular to the plane of the coil. The coil has a resistance of 2.50 ohms. If the magnetic field reverses direction in a time of 0.350 seconds, what is the induced voltage and the induced current? Is the current clockwise or counterclockwise as viewed from above the coil? ( -5.71 V, I-2.29 A) 6. A single wire loop (diameter 20.0 cm) is stationary in the center of a solenoid with the upward magnetic field of the solenoid perpendicular to the plane of the loop. The loop has a resistance of 1.40 ohms. If the current in the solenoid rise from 2.00 A to 5.50 A in 0.150 second what is the induced voltage and induced current in the loop? The solenoid has 500 turns and is 10.0 cm long. Is the current clockwise or counterclockwise as viewed from above the coil? (-4.60x103 V, I 3.29x103 A) 7. A neon sign, that requires an RMS voltage of 11000V, is plugged into the wall outlet at 120 V RMS. If there are 100 turns in the primary coils for the transformer, how many turns are in the secondary? The power output of the sign is 800 W. What is the secondary RMS current, What is the primary RMS current? Assu (N2-9170, I2 72.3 mA, I 6.67 A) me a perfect transformer 8. A capacitor is attached to a 120 V RMS voltage source. The RMS current through the capacitor is 0.750 A. If the capacitor has a value of 4.70 nF, what is the frequency?( 212x105/s-212kHz) This is only review for chapters 20 and 21. Look at the current homework assignment for chapter 22 and 23 problems.Explanation / Answer
2. Fnet = Fb + Fe = 0
0 = Fb + (-1.6x 10^-19 x 450 j)
Fb = 7.21 x 10^-17 N j
Fb = q ( v x B )
7.21 x 10^-17 j = (-1.6 x 10^-19) [ (2.5 x 10^5)i x B]
B = 1.80 x 10^-3 k
v and B are same for He hence Fb = Fe
so Fnet = 0
Ans: Magnitude = 1.80 x 10^-3 T
direction = along +x z axis
same path . (still net force is zero.)
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