PHYS 212 Sample Final Exam 1 In the circuit shown the light bulb has a resistance R and the ac emf drives the circuit with a frequency cid 90 Assuming that the brightness of a bulb is proportional to the power dissipated which of the following statements is correct A The light bulb glows most brightly at very low frequencies B The light bulb does not glow at any frequency because AC current cannot flow through the bulb due to the presence of the capacitor C The light bulb glows most brightly at very high frequencies D The light bulb glows with the same brightness at all frequencies E The light bulb glows most brightly at the frequency cid 90 cid 32 1 LC 2 100 coulombs of charge pass through a resistor at a constant rate in 10 seconds During this time 1000 joules of heat energy are produced in the resistor as a result of the charge flowing through What is the resistance of the resistor A 1000 cid 58 B 0 1 cid 58 C 10 cid 58 D 100 cid 58 E 1 cid 58 3 You measure the voltage across a circuit element in an AC circuit as the frequency increases from a small to a large value You observe that the output voltage is essentially the same as the input EMF initially but as you increase the frequency beyond a certain point the output voltage begins to decrease in amplitude You must be measuring the voltage across A C in an RC circuit B L in an RLC circuit C L in an RL circuit D R in an RC circuit E R in an RLC circuit Page 1 4 An electron traveling north enters a region where the electric field is uniform and points west The PHYS 212 Sample Final Exam electron A continues with the same speed northwards B veers east C slows down northwards D speeds up northwards E veers west 5 An inductance L and a resistance R are connected in series to an ideal battery A switch in the circuit is closed at time 0 at which time the current is zero The energy stored in the inductor is a maximum A a long time after the switch is closed B at the time t L 2R after the switch is closed C just after the switch is closed D at the time t 2L R after the switch is closed E at the time t L R after the switch is closed Page 2 PHYS 212 Sample Final Exam 6 A mass spectrometer is shown below A charged particle of mass m and charge q enters the lower chamber with E and B B points into the paper and moves in a straight line It then enters into the upper chamber with no electric field and a magnetic field that still points into the paper but with a different magnitude B0 What is the radius of curvature of the particle s trajectory in the upper chamber What is the radius of curvature r of the arc through which the particle moves A r cid 32 B r C r D r E r cid 32 cid 32 cid 32 cid 32 mE qBB 0 0mB qBE mB qB E 0 qEB 0 mB qBB 0 mE Page 3 PHYS 212 Sample Final Exam 7 The figure below shows a spherical conducting shell surrounding an uncentered conducting sphere that carries an excess charge of Q If an excess charge of 6Q is placed on the conducting shell how does this charge distribute itself on the inner and outer surfaces of the shell 8 According to Maxwell s equations a displacement current exists in the region between the plates A 0Q inside 6Q outside B Q inside 5Q outside C Q inside Q outside D Q inside 7Q outside E There is not enough information to tell of a parallel plate capacitor A whenever the capacitor leaks charge across the plates B while the capacitor is being discharged C a long time after the capacitor has been fully charged D a long time after the capacitor has been fully discharged E none of the above are true 9 The magnetic properties of materials stem chiefly from A particles with north poles B particles with south poles C proton spin angular momentum D electron magnetic dipole moments E motions of protons within nuclei Page 4 PHYS 212 Sample Final Exam 10 A R 0 70 m radius cylindrical region contains a uniform electric field that is parallel to the axis and is increasing at the rate 5 0 1012 V m s The magnetic field at a point r 1 2 m from the axis has a magnitude of A 0 B 1 1 10 5 T C 7 0 10 6 T D 5 5 10 6 T E 3 5 10 6 T Page 5 PHYS 212 Sample Final Exam 11 The figure shows a phasor diagram for a series RLC circuit Which of the following statements is correct Note that the figure is drawn to scale A The drive frequency is below the resonance frequency V1 is the voltage drop across the inductor V2 is the voltage drop across the resistor and V3 is the voltage drop across the capacitor B The drive frequency is above the resonance frequency V1 is the voltage drop across the capacitor V2 is the voltage drop across the resistor and V3 is the voltage drop across the inductor C The drive frequency is below the resonance frequency V1 is the voltage drop across the resistor V2 is the voltage drop across the inductor and V3 is the voltage drop across the capacitor D The drive frequency is above the resonance frequency V1 is the voltage drop across the resistor V2 is the voltage drop across the inductor and V3 is the voltage drop across the capacitor E The drive frequency is above the resonance frequency V1 is the voltage drop across the inductor V2 is the voltage drop across the resistor and V3 is the voltage drop across the capacitor 12 An electromagnetic wave has electric and magnetic fields E and B and propagates with a velocity v Which of the below are required A E must be perpendicular to B B v must be perpendicular to E C v must be perpendicular to B D All of the above E None of the above Page 6 PHYS 212 Sample Final Exam 13 In the circuit shown below R1 2 00 cid 58 R2 3 00 cid 58 L 30 0 mH and E 12 0 V The switch is closed at t 0 s Immediately after the switch is closed what is the current through resistor R1 14 In the driven RLC circuit shown if R 15 cid 58 L 27 mH C 3 mF Em 34 V and cid 90 is one third of the resonant frequency what is the peak current A 0 00 A B 6 00 A C 2 40 A D 10 A E 4 00 A A 2 3 A B 1 4 A C …