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Electromagnetics Electrical CircuitsThe electron orbits around a proton in a hydrogen atom at a mean radius of 5.3x10-11 m. Find the magnitude of the electric force on the electron.2.6x10-5 N8.2x10-8 N4.9x10-8 N7.5x10-6 N2.An electron is released from rest in a uniform electric field of magnitude 2x104V/m. Calculate the acceleration of the electron.5.32x1015 m/s22.53x1015 m/s23.52x1015 m/s23.25x1015 m/s23.An infinite line of charge produces a field of magnitude 4.5x104 V/m at distance 2 m. Find the linear charge density.3 C/m4 C/m5 C/m6 C/m4.What is the magnitude of the electric field required to store 1 J of electric potential energy in a volume of 1 m3 in a vacuum?0.625 MV/m0.5 MV/m0.475 MV/m0.45 MV/m5.What is the drift speed of conduction electrons in a copper wire with radius r = 900 m when it has a uniform current I = 17 mA? ncu = 8.49x1028 /m3?2.1x10-7 m/s4.9x10-7 m/s6.7x10-6 m/s5.3x10-6 m/s6.Wire B has twice the length and twice the radius of wire A. Both wires are made from the same material. If wire A has a resistance R, what is the resistance of wire B?4R2R0.5R0.25R7.A uniform magnetic field with magnitude 1.2 mT, is directed vertically upward throughout the volume of a laboratory chamber. A proton with kinetic energy 5.3 MeV enters the chamber, moving horizontally from south to north. What magnetic deflecting force acts on the proton as it enters the chamber?5.3x1012 N6.1x1015 N6.1x10-15 N1.6x10-15 N8.A magnetron in a microwave oven emits electromagnetic waves with frequency 2.45 GHz. What magnetic field strength is required for electrons to move in circular paths with frequency?52.5 mT62.5 mT87.5 mT90.0 mT9.A 2 m long wire weighs 4 g and carries a 10 A current. It is constrained to move only vertically above another wire carrying 15 A in the opposite direction. At what separation would its weight be supported by magnetic force?2.64 mm1.53 mm4.47 mm3.12 mm10.A solenoid 1.3 m long and 2.6 cm in diameter carries a current of 18 A. The magnetic field inside the solenoid is 23 mT. Find the length of the wire forming the solenoid.180 m108 m190 m110 m11.A 500-loop circular wire coil with radius 4 cm is placed between the poles of a large electromagnet. The magnetic field is uniform and makes an angle of 60 degrees with the plane of the coil; it decreases at 0.2 T/s. What is the magnitude of the induced emf?4.35 V43.5 V0.435 V0.345 V12.The armature of a small generator consists of a flat, square coil with 120 turns and sides with a length of 1.6 cm. The coil rotates in a magnetic field of 0.075 T. What is the RPM of the coil if the maximum emf produced is 24 mV?50 RPM100 RPM150 RPM200 RPM13.An air-filled toroidal solenoid has a mean radius of 15 cm and a cross sectional area of 5 cm2. When the current is 12 A, the energy stored is 0.39 J. How many turns does the winding have?258028508250852014.The resistance of a wire is 126.48 ohms at 100oC and 100 ohms at 30oC. Determine the temperature coefficient at 0oC..0.006150.004270.01230.11115.Two 115 V incandescent lamp A and B are connected in series across a 230 V source. If lamp A is rated 75 W and lamp B is rated 50 W, determine the current drawn by the series connection.0.64 A0.52 A0.48 A0.57 A16.A battery formed of five cells is joined in series. When the external resistance is 4 ohm, the current is 1.5 A and when the external resistance is 9 ohms, the current falls to 0.75 A. Find the internal resistance of each cell.0.350.20.250.317.A term used to describe how fast an energy is consumed.Resistive LoadVoltsPowerConductance18.Why is the resistance of a conductor different for RF current than for DC?Because of the Heisenberg EffectBecause of the Skin EffectBecause of the Edison EffectBecause the insulation conducts at radio frequency19.An alternating current varying sinusoidally with frequency of 50 Hz has an RMS value of 20 A. At what time measured from the positive maximum value will the instantaneous current be 14.14 A?1/600 sec1/300 sec1/200 sec1/400 sec20.The following is power dissipated by the resistive components of the circuit, except:ActiveApparentAverage True21.Which of the following best describes an inductance?Tends to oppose DCTends to oppose changes in currentTends to oppose changes in voltageOpposes certain values of frequencies22.In a circuit that has both inductors and capacitors, what happens to reactive power?It is dissipated as heat in the circuitIt goes back and forth between magnetic and electric field but it is not dissipatedIt is dissipated as kinetic energy in thec circuitReactive power will be zero23.Three alternating currents given by i1 = 141sin(wt + 45); i2 = 30sin(wt + 90); i3 = 20cos(wt 120). Find the equation of the resultant current.167.4sin(wt + 45.66)74.6sin(wt)143.8sin(wt + 51.4)64.7sin(wt 30)24.A resistor R and a capacitor C are connected in series across a 100 V, 60 cycle source. The reading of an ammeter connected in the circuit is 2 A and the reading of a voltmeter connected across the capacitor is 80 V. Calculate the values of R and C.66 ohm and 30 uF30 ohm and 60 uF30 ohm and 66 uF36 ohm and 60 uF25.A series circuit consists of a 66.2 uF capacitor and a variable resistor. For what two values of resistance will the power taken by the circuit be 172.8 W, if the impressed 60 cycle emf is 120 V?83.33 ohms and 3.33 ohms53.33 ohms and 30 ohms5.33 ohms and 3.0 ohms83.33 ohms and 5.33 ohms