100%(1)1 out of 1 people found this document helpful
This preview shows page 13 - 17 out of 21 pages.
23.Aeroflot.An airplane is flying in such a way that the Earth’s magnetic field, with local fieldstrength0.30 mT, forms an angle of30◦relative to the direction of motion of the airplane.If the plane is cruising at a speed of150 m/s, and if the plane has a wingspan of10 m, whatis the induced EMF across the plane’s wings?A.0.003 VB.0.225 VC.0.390 VD.0.450 VSolution:vBLsinθ24.Electrostatic vs induced.Which of the following statements is ALWAYS TRUE?I. The notion of the potential difference makes sense only for electrostatic fields.II. The work done by induced electric fields on a point charge moved along a closed pathis zero.III. The work done by electrostatic fields are path-dependent.B – 13
Second Long ExamMidyear, AY 2015–2016Physics 72Solution:yeah25.All by myself.A coil has a self inductance of0.5 H. If the current in coil 2 varies asI(t) = 3t2-4t(in SI units), what will be the magnitude of the induced emf in the coilafter1 s?26.MU.Two solenoids have an unknown mutual inductance. The EMF in solenoid 1 is3.0 Vwhen the current in solenoid 2 changes by1.0 A/s. What is the EMF in solenoid 2 whenthe current in solenoid 1 changes by2.0 A/s?.
B – 14
Second Long ExamMidyear, AY 2015–2016Physics 7227.induc-THOR.An inductor coil has self-inductanceL= 40μH.The currentiin thisinductor decreases uniformly from8.0 Ato4.0 Ain2.0μs. What is the magnitude anddirection of the self-induced emf?A.20 V, along the direction ofiB.40 V, opposite the direction ofiC.80 V, along the direction ofiD.240 V, opposite the direction ofiSolution:|E|=L|didt|, deccreasing current: direction of emf same with direction ofcurrent28.Solenoid Heussaff.A tightly wound solenoid withNturns and lengthlcarries currentI.What is the magnetic energy density inside the solenoid?2I2N2I22μ0l2C.μ0N2I22N2I229.I-induct na lamang.A coil that has a self-inductance of2.00 Hand a resistance of12.0 Ωis connected to an ideal24.0-Vbattery. How much energy is stored in the inductor whenthe steady-state current is established?12.0 Ω= 2.00 ACalculate for the energy stored in the inductor.U=12LI2=12(2.00 H)(2.00 A)