CPFinal

A coaxial cable consists of a solid inner cylindrical conductor of radius 2.0 mm and an outer cylindrical shell of inner radius 4.0 mm and outer radius 4.2 mm. A current of 15 A flows down the inner wire and an equal return current flows in the outer conductor. Find the magnetic field at a radius of 3.0 mm (hint: B2pir=uI - B=uI/2pir) A) 1.0 mT B) 2.0 mT C) 3.7 mT D) 4.0 mT E) 6.3 mT

A) 1.0 mT

You connect a 100 ohm resistor, an 800 mH inductor, and a 10 uF capacitor in series across a 60 Hz, 120 V (peak) source. The maximum current in this circuit is approximately A) 1.12 A B) 1.59 A C) 1.20 A D) 1.69 A E) 792 mA

A) 1.12 A (E=IZ; Xc=1/2pifC; Xl=2pifL)

The resistance of the unknown resistor R is: A) 2 ohm B) 3 ohm C) 4 ohm D) 5 ohm E) 8 ohm

A) 2 ohm

A series circuit consists of a 40 V battery, a 40 ohm resistor, a 2 H inductor and an open switch. At t=0 s the switch is closed. At some time later the current through the resistor is .4 A. At this time, at what rate is energy being stored in the magnetic field of the inductor? A) 9.6W B) 10.2 W C) 12.0 W D) 1.8 W E) 13.8 W

A) 9.6W (EI-I^2R=rate energy stored)

When the switch S is open, the ammeter in the circuit shown reads 2.0 A. When S is closed, the ammeter reading: A) increases slightly B) remains the same C) decreases slightly D) doubles E) halves

A) increases slightly

In a certain region of space the electric potential decreases uniformly from West to East and does not vary in any other direction. The electric field: A) points East and does not vary with position B) points East and varies with position C) points West and varies with position D) points West and does not vary with position E) points North and does not vary with position

A) points East and does not vary with position

Points R and T are each a distance d from each of two equal positive charges as shown. The work required to move a particle with a charge q from R to T is: A. 0 B. kQq/d^2 C. kQq/d D. kQq/(2d)^1/2 E. kQq/(2d)

A. 0

The electrostatic potential energy of the system o point charges q1=-1uC, q2=2uC, and q3=3uC at corners of equilateral triangle whose sides s=50 cm is: A. 18 mJ B. -18.0 mJ C. -24.4 mJ D. 21.6 mJ E. 1.23 mJ

A. 18 mJ (kq1q2/s+kq2q3/s+kq1q3/s)

Two small spheres attract one another electrostatically. This can occur for a variety of reasons. Which of the following statements must be true? A. At least one sphere is charged B. neither is charged C. both are charged D. both have the same charge E. none of the above

A. At least one sphere is charged

Experimenter A uses a test charge of qo and experimenter B uses a test charge of 2qo to measure an electric field produced by stationary charges. Experimenter A finds a field that is: A. The same as the field found by B B. greater than the field found by B C. less than the field found by B. D. either greater or less than the field found by B, depending on the masses of the test charges E. either greater or less than the field found by B, depending on the acceleration of the test charges

A. The same as the field found by B

An infinite slab of thickness 2d lies in the xz plane. Slab has uniform volume charge density p. Using symmetry and Gaussian Law show that the electric field for y when 0<y<d A. py/Eo B. py/2Eo C. p/yEo D. p/2yEo E. p/y^2Eo

A. py/Eo

Two solenoids are concentric. Te inner solenoid has a radius of 5.0 cm and the outer one has a radius of 10 cm. Each has a length of 50 cm and each has 200 turns of close packed copper wire. The mutual inductance of the two solenoids is (hint: M=un1n2lAm) A) 1.6 mH B) 0.80 mH C) 3.2 mH D) 4.8 mH E) 6.3 mH

B) 0.80 mH

Two conducting spheres, one having twice the diameter of the other, are separated by a distance large compared to their diameters. The smaller sphere (1) has charge q and the larger sphere (2) is uncharged. If the spheres are connected by a long thin wire: A) 1 and 2 have the same charge B) 1 and 2 have the same potential C) 2 has twice the potential as 1 D) 2 has half the potential as 1 E) 1 has twice the charge as 2

B) 1 and 2 have the same potential

A 3 ohm and a 6 ohm resistor are connected in parallel to a 12 V battery. What power is dissipated by the 6 ohm resistor? A) 16 W B) 24 W C) 48 W D) 60 W E) 72 W

B) 24 W

The current in the 3 ohm resistor is 2 A. What is the current in the 2 ohm resistor? A) 2 A B) 3 A C) 4 A D) 5 A E) none of these is correct

B) 3 A

The magnetic flux through a certain coil is given by phi=(1/50pi)cos100pit. The units are S.I. The coil has 200 turns. The magnitude of the induced emf when t=1/200 s is: A) 200 V B) 400 V C) zero D) 1/2pi V E) 1/50pi V

B) 400 V

In the figure the potential difference V is 12.0 V, C1=4.0 uF, C2=8.0 uF, C3=12 uF. What is the charge on C3? A) 26 uC B) 72 uC C) 144 uC D) 176 uC E) 288 uC

B) 72 uC

A charge capacitor is being discharged through a resistor. At the end of one time constant the charge ha been reduced by (1-1/e)-63% of its initial value. At the end of two time constants the charge has been reduced by what percent of its initial value? A) 82% B) 86% C) 100% D) between 90% and 100% E) need more to answer this

B) 86% (1-e^-2=0.86)

A charged capacitor and an inductor are connected in series. At time t=0 the current is zero, but the capacitor is charged. If T is the period of the resulting oscillations, the next time, after t=0 that the current is a maximum is: A) T/2 B) T/4 C) 3T/4 D) 3T/2 E) 2T

B) T/4

A series circuit consists of a battery, a light bulb, an inductor and a switch. The time constant for the RL circuit is of the order of a few seconds. What happens to the light bulb when the switch S is closed? A) The light comes on immediately then gradually dims, going off in a few seconds B) The light comes on gradually in a few seconds and stays on C) The light does not come on at all D) The light comes on in a few seconds then goes off instantaneously E) The light comes on in a few seconds then goes off in a few seconds

B) The light comes on gradually in a few seconds and stays on

Which of the following statements contradicts one of Maxwell's equations? A) A changing magnetic field produces an electric field B) The net magnetic flux through a closed surface depends on the current inside C) A changing electric field produces a magnetic field D) The net electric flux through a closed surface depends on the charge inside E) None of these statements contradict any of Maxwell's equations

B) The net magnetic flux through a closed surface depends on the current inside

The rapid decay of charge in just a few cycles on the capacitor in an undriven RLC circuit might be due to: A) a small resistance B) a large resistance C) a large capacitance D) a small capacitance E) a large inductance

B) a large resistance

An electromagnetic wave is created by: A) any moving charge B) any accelerating charge C) only a charge with changing acceleration D) only a charge moving in a circle E) only a charge moving in a straight line

B) any accelerating charge

A long straight wire is in the plane of a rectangular conducting loop. The straight wire carries a decreasing current in the direction shown. Te current in the rectangle is: ^ | | A) zero B) clockwise C) counterclockwise D) clockwise in the left side and counterclockwise in the right side E) counterclockwise in the left side and clockwise in the right side

B) clockwise

Two wires are made of the same material and have the same length but different radii. They are joined end to end and a potential difference is maintained across the combination. Of the following the quantity that must be the same for both wires is: A) potential difference B) current C) current density D) electric field E) conduction electron drift speed

B) current

Pulling the plates of an isolated charge parallel plate capacitor apart: A) increases the capacitance B) increases the potential difference C) does not affect the potential difference D) decreases the potential difference E) does not affect the capacitance

B) increases the potential difference

In a sinusoidally driven series RLC circuit the current leads the applied emf. The rate at which energy is dissipated in the resistor can be increased by: A) decreasing the capacitance and making no other changes B) increasing the capacitance and making no other changes C) decreasing the inductance and making no other changes D) decreasing the driving frequency and making no other changes E) increasing the amplitude of the driving emf and making no other changes

B) increasing the capacitance and making no other changes

A toroid with a square cross section carries current I. The magnetic field has its largest magnitude: (hint: B=uNI/2pir) A) at the center of the whole B) just inside the toroid at its inner surface C) just outside the toroid at its outer surface D) at any point inside (the field is uniform) E) at none of the above

B) just inside the toroid at its inner surface

A plastic rod of length L=4.0 m, has a nonuniform linear charge density lambda=cx, where c=0.5 C/m^2. With V=0 at infinity, with k being the Coulomb constant, what is the potential at point P=(0,y) with y=3.0 m? A) 0.4k B) k C) 1.6k D) 2.5k E) 2.7k

B) k

The magnetic torque exerted on a flat current-carrying loop of wire by a uniform magnetic field B is: A) maximum when the plane of the loop is perpendicular to B B) maximum when the plane of the loop is parallel to B C) dependent on the shape of the loop for a fixed loop area D) independent of the orientation of the loop E) such as to rotate the loop around the magnetic field lines

B) maximum when the plane of the loop is parallel to B

The electric potential in a certain region of space is given by V=-7.5x^2+3x, where V is in volts and x is in meters. In this region the equipotential surfaces are: A) planes parallel to the x axis B) planes parallel to the yz plane C) concentric spheres centered at the origin D) concentric cylinders with the x axis as the cylinder axis E) unknown unless the charge is given

B) planes parallel to the yz plane

A cylindrical region o radius R contains a uniform magnetic field, parallel to its axis, with magnitude that is changing linearly with time. If r is the radial distance from the cylinder axis, the magnitude of the induced electric field inside the cylinder is proportional to: (hint: phi=(1/50pi)cos(100pit)) A) R B) r C) r^2 D) l/r E) l/r^2

B) r

A uniform magnetic field is directed into the page. A charged particle, moving in the plane of the page, follows a CLOCKWISE spiral of decreasing radius as shown. A reasonable explanation is: A) the charge is positive and slowing down B) the charge is NEGATIVE and slowing down C) the charge is positive and speeding up D) the charge is NEGATIVE and speeding up E) none of the above

B) the charge is negative and slowing down

An electric field is E=400 N/C for x>0 and E=-400N/C for x<0. A Gaussian cylinder of length 30 cm and radius 10 cm has its center at origin and axis along the x-axis so that x=15 cm and x= -15 cm. What is the net charge inside the cylinder? A. 0 B. .22nC C. 22 nC D. 4.5 nC E. 2.2 uC

B. .22nC

Particles 1, with a charge q, and 2, with a charge q2 are on the x-axis, with particle 1 at x=a and particle 2 ar x=-2a. For the net force on a third charged particle at the origin to be zero q1 and q2 must released by q2=: A. 2q B. 4q C. -2q D. -4q E. -q/4

B. 4q

The diagram shows the electric field lines due to two parallel plates. We conclude that: A. the upper plate is positive and the lower plate is negative B. A proton at x would experience the same force if it were placed at y. C. a proton at X experiences a greater force that if it were placed at Z D. a proton at X experiences less force that if it were placed at Z E. en electron at X could have its weight balanced by the electric force

B. A proton at x would experience the same force if it were placed at y.

The electric field for r>rb2 is: A. -kQ/r^2 B. kQ/r^2 C. 2kQ/r^2 D. -2kQ/r^2 E. 0

B. kQ/r^2

The electric field for rs<r<rb1 is: A. -kQ/r^2 B. kQ/r^2 C. 2kQ/r^2 D. -2kQ/r^2 E. 0

B. kQ/r^2

A capacitor in an LC oscillator has a maximum potential difference of 15 V and a maximum energy of 360 uJ. At a certain instant the energy in the capacitor is 40 uJ. At the instant what is the emf induced in the inductor? A) zerio B) 5 V C) 10 V D) 15 V E) 20 V

C) 10 V (Ue=Q^2/2C=1/2CVc^2; Vc+Vl=15)

The maximum E-component of an electromagnetic wave is 600 V/m, what is the maximum B-component? A) 1.4 T B) 1.8x10^11 T C) 2.0x10^-6 T D) 1.0x10^-3 T E) 1.6x10^-10 T

C) 2.0x10^-6 T (B=E/C)

The potential difference between the ends of a 2-meter stick that is parallel to a uniform electric field is 400 V. The magnitude of the electric field is: A) 0 B) 100 V/m C) 200 V/m D) 400 V/m E) 800 V/m

C) 200 V/m

A flat iron is marked "120 volt, 600 watt". In normal use the current in it is: A) 2 A B) 4 A C) 5 A D) 7.2 A E) 0.2 A

C) 5 A

A capacitor, C1=5.0 uF, is charged to 8.0 V. It is then connected to an uncharged capacitor, C2=2.5 uF. The voltage across C1 after equilibrium is reached is: A) 2.7 V B) 4.0 V C) 5.3 V D) 8.0 V E) 12 V

C) 5.3 V

You connect a 100 ohm resistor, an 800 mH inductor, and a 10 uF capacitor in series across a 60 Hz, 120 V (peak) source. The resonant frequency in this circuit is approximately A) 354Hz B) 60 Hz C) 56 Hz D) 37 Hz E) 165 Hz

C) 56 Hz (f=1/2pisquarerootLC)

A coil has resistance of 80 ohm and an impedance of 100 ohm. Its reactance in ohm is: A) 20 B) 40 C) 60 D) 117 E) 160

C) 60 (z^2=sqaure root R^2+X^2)

A parallel plate capacitor of separation distance d=4.0 mm, has a dielectric slab of thickness b=3.0 mm and dielectric constant k=3.0. The capacitor is connected to a 15 V source. What is the magnitude of the electric field in the gap between the dielectric and the top plate? A) 3.0 kV/m B) 5.0 kV/m C) 7.5 kV/m D) 15 kV/m E) 30 kV/m

C) 7.5 kV/m

Two isolated, concentric, thin metal sperial shells have radii a and b as shown. The inner shell has an excess charge Q1 and the outer shell has excess charge Q2, both positive. With V=0 at infinity, what is the electric potential at a distance r where a<r<b? A) kQ1/r B) k(Q1+Q2)/r C) kQ1/r+kQ2/b D) kQ1/a+kQ2/b E) kQ1/r-kQ2/b

C) kQ1/r+kQ2/b

An electromagnetic wave is transporting energy in the positive y direction. At one point and one instant the magnetic field is in the positive x direction. The electric field at that point and instant is: A) positive y direction B) negative y direction C) positive z direction D) negative z direction E) negative x direction

C) positive z direction

In each of the following operations energy is expended. The LEAST percentage of electrical energy will be yielded by: A) charging a capacitor B) charging a storage battery C) sending a current through resistor D) sending a current through an inductor

C) sending a current through resistor

Faraday's law states that an induced emf is proportional to: (hint: Eind=-dphim/dt) A) the time rate of change of the magnetic field B) the time rate of change of the electric field C) the time rate of change of the magnetic flux D) the time rate of change of the electric flux E) zero

C) the time rate of change of the magnetic flux

Charge is distributed uniformly on the surface of a very large flat conducting surface. The electric field 2 cm from the plate is 30 N/C. The electric field 4 cm from the plate is: A. 120N/C B. 80 N/C C. 30 N/C D. 15 N/C E. 7.5 N/C

C. 30 N/C

When a positive charge is released from rest in a region of space where there is a uniform electric field it will: A. move at a constant speed B. move at a constant velocity C. move at a constant acceleration D. move with a linearly changing acceleration E. remain at rest in its original position

C. move at a constant acceleration

A conductor is distinguished from an insulator with the same number of atones by the number of: A. nearly free atoms B. electrons C. nearly free electrons D. protons E. molecules

C. nearly free electrons

When a rubber rod is given a negative charge by rubbing it with fur: A. the fur becomes negative B. the fur becomes neutral C. the fur becomes positive D. the fur creates negative charge to give to the rod E. the rod creates negative charge

C. the fur becomes positive

A capacitor in a flash camera is charged by a V battery. When the camera flashes , this capacitor is discharged through an 8.3 kilo-ohm resistor. The time constant of the circuit is 10 ms. What is the value of the capacitance? A) 0.2 uF B) 3.2 uF C) 0.83 uF D) 1.2 uF E) 83 uF

D) 1.2 uF (Tau=RC)

A 1.2 m radius cylindrical region contains a uniform electric field that is increasing uniformly wiht time. At t=0 the field is 0 and at t=5.0 s the field is 200 V/m. The total displacement current through a cross section of the region is: A) 4.5x10^-6 A B) 2.0x10^-15 A C) 3.5x10^-10 A D) 1.6x10^-9 A E) 8.0x10^-9 A

D) 1.6x10^-9 A (I=epsilonAdE/dt)

What is the magnetic field at the center of a circular loop with a diameter of 15.0 cm that carries a current of 1.50 A? (hint: B=uI/2R) A) zero B) 6.28 uT C) 25.1 uT D) 12.6 uT E) 168 uT

D) 12.6 uT

A potential difference of 12 V will be applied to a 35 m length of copper wire of diameter 1.0 mm. The resistivity of copper is 1.7x10^-8 ohlms*m. What is the rate at which thermal energy will appear in the wire? A) 16 W B) 38 W C) 95 W D) 190 W E) 760 W

D) 190 W

Capacitors A and B are identical. Capacitor A is charged so it stores 4 J of energy and capacitor B is uncharged. The capacitors are then connected in parallel. The total stored energy in the capacitors is now: A) 16 J B) 8 J C) 4 J D) 2 J E) 1 J

D) 2 J

An ordinary light bulb is marked "60 watt, 120 volt". Its resistance when on for a while is: A) 60 B) 120 C) 180 D) 240 E) 15

D) 240

A certain wire has resistance R. Another wire, of the same material, has half the length and half the diameter of the first wire. The resistance of the second wire is: A) R/4 B) R/2 C) R D) 2R E) 4R

D) 2R

Two large conducting plates are separated by a distance d, placed in a vacuum, and connected to a source of potential V. An alpha particle (2 protons and 2 neutrons) starts from rest on the surface of one plate and accelerates to the other. If e denotes the magnitude of the proton charge, the final kinetic energy of this particle is: A) eV/2 B) eV/d C) eVd D) 2eV E) Vd/e

D) 2eV

An electron passes through a region where there is an electric field of 4.0 x 10^5 V/m and a magnetic field of 0.090 T. The direction of the magnetic field, the electric field and electron velocity are all mutually perpendicular. If the electron is not deflected from its straight line path its velocity must be: (hint: Fe=Fb - qE=qvB - v=E/B= 4 x 10^5/0.09) A) 3.6 x 10^4 m/s B) 2.2 x 10^-7 m/s C) 5.0 x 10^5 m/s D) 4.4 x 10^6 m/s E) 1.2 x 10^4 m/s

D) 4.4 x 10^6 m/s

Radio receivers are usually tuned by adjusting the capacitance of an LC circuit. If C=C1 allows you to receive a 1600 kHz station ten for a 800 kHz station you must adjust C to: A) C1/2 B) C1/4 C) 2C1 D) 4C1 E) square root 2C1

D) 4C1 (f1/f2=square rootC2/square root C1)

What is the power dissipated in the 16 ohm resistor in the circuit below? A) 8.0 W B) 0.25 W C) 0.50 W D) 5.0 W E) 3.2 W

D) 5.0 W

A wire rod rolls with a speed of 20 mm/s on two metallic rails, 1.0 m apart, that form a closed loop. If the magnetic field is 1.5 T into the page, the power dissipated in the resistor R and the current direction are, respectively, (hint: phi=Blx, E=dphi/dt=Blx) A) 33 mW, counterclockwise B) 33mW, clockwise C) 76 mW, counterclockwise D) 76 mW, clockwise E) 50 mW, clockwise

D) 76 mW, clockwise

Which of the following statements is false? A) An electric field is needed to produce an electric current. B) A potential difference between two points is needed to produce an electric current. C) For a steady current to flow in a wire, the wire must be part of a closed circuit. D) The electric field is constant along all parts of any circuit when a steady current is flowing. E) The electric current in a wire is proportional to the drift velocity of the charges.

D) The electric field is constant along all parts of any circuit when a steady current is flowing.

A device used chiefly for storing energy in a magnetic field is A) a resistor B) a capacitor C) a galvanometer D) an inductor E) a dielectric

D) an inductor

A certain battery is rated at 80 A*h. An ampere-hour is a unit of: A) power B) energy C) current D) charge E) voltage

D) charge

An Ampere's lae, B*dl=uI the integration must be over any: A) surface B) closed surface C) path D) closed path E) closed path that surrounds all the currents producing B

D) closed path

The electron volt is a unit of A) charge B) capacitance C) potential D) energy E) momentum

D) energy

An RL series circuit is connected to an emf source having angular frequency w. The current: A) leads the source emf by tan^-1(R/wL) B) lags the source emf by tan^-1(R/wL) C) leads the source emf by tan^-1(wL/R) D) lags the source emf by tan^-1(wL/R) E) leads the source emf by pi/4

D) lags the source emf by tan^-1(wL/R)

Magnetism is produced by: A) an excess of north or south monopoles B) a separation of positive and negative charges C) Movement of magnetic charges D) movement of electric charged particles E) an alignment of electric fields

D) movement of electric charged particles

The radius of curvature of the path of a charged particle moving perpendicular to a magnetic field is given by: A) qE/m B) Bm/(qv) C) Bv/(qm) D) mv/(qB) E) Bq/(mv)

D) mv/(qB)

If the charge on a parallel plate capacitor is doubled: A) the capacitance is halved B) the capacitance is doubled C) the electric field is halved D) the electric field is doubled E) the surface charge density is not changed on either plate

D) the electric field is doubled

Two of Maxwell's equations contain a path integral on the left side and an area integral on the right. For them: A) the path must pierce the area B) the path must be well-separated from the area C) the path must be along a field line and the area must be perpendicular to the field line D) the path must be the boundary of the area E) the path must lie in the area, away from its boundary

D) the path must be the boundary of the area

The charge on each capacitor in a set of capacitors in series is: A) directly proportional to its capacitance B) inversely proportional to its capacitance C) independent of its capacitance D) the same E) greater than the charge when they are connected in parallel

D) the same

The concept of difference in electric potential is most closely associated with: A) the mechanical force on an electron B) the number of atoms in one gram C) the charge on an electron D) the work per unit quantity of charge E) the electric field due to a point charge

D) the work per unit quantity of charge

Magnetic field lines inside the solenoid shown are: <--- I ---> I A) clockwise circles as one looks down the axis from the top of the page B) counterclockwise circles as one looks down the axis from the top of the page C) toward the bottom of the page D) toward the top of the page E) in no direction since B=0

D) toward the top of the page

A uniform line charge of linear charge density lambda=5nC/m extends from x=0 to x=10m. The magnitude of the electric field at x=12m is: A. 3.86 N/C B. 9.62 N/C C. 15.3 N/C D. 18.8N/C E. 37.5 N/C

D. 18.8N/C

A point particle with charge q is placed at the center of a sperical Gaussian surface. The electric flux phi is changed if: A. the sphere is replaced by a cube of the same volume B. the sphere is replaced by a cube of about one-tenth the volume C. the point charge is moved off center but still inside the sphere D. The point charge is moved just outside the sphere e. all of the above

D. The point charge is moved just outside the sphere

The electric field due to a uniform distribution of charge on a spherical shell is zero: A. everywhere B. nowhere C. only at the center of the shell D. only inside the shell E. only outside the shell

D. only inside the shell

A point particle with a charge q is at the center of a Gaussian surface in the form of a cube. The electric flux through any one face of the cube is: A. q/Eo B. q/4piEo C. q/4Eo D. q/6Eo E. q/16Eo

D. q/6Eo

An electron traveling west enters a region where the electric field is in uniform and points north. The electron: A. speeds up B. slows down C. veers north D. veers south E. continues with the same speed in the same direction

D. veers south

Charge is distributed uniformly along a very long straight wire. The electric field 2 cm from the wire is 20 N/C. The electric field 4 cm from the wire is: A. 120 N/C B. 80 N/C C. 40 N/C D.10 N/C E. 5 N/C

D.10 N/C

In an oscillating LC circuit, the total stored energy is U and the maximum charge on the capacitor is Q. When the charge on the capacitor is Q/2, the energy stored in the inductor is: A) U/2 B) U/4 C) (4/3)U D) 3U/2 E) 3U/4

E) 3U/4 (Ue=Q^2/2C)

A metal sphere carries a charge of 2.5x10^-9C and is at a potential of 500 V, relative to the potential far away. The potential at the center of the sphere is: A) 0 B) infinite C) 2.5x10^-6V D) -500 V E) 500 V

E) 500 V

The sum of the emf's and potential difference around a closed loop equals zero is a consequence of: A) Newton's third law B) Ohm's law C) Newton's second law D) Conservation of charge E) Conservation of energy

E) Conservation of energy

In the diagrams, all light bulbs are identical and all emf devices are identical. In which circuit (I, II, III, IV, V) will the bulbs be brightest (have the most current)? A) I B) II C) III D) IV E) V

E) V

A proton moves north in a region where the magnetic field points up. The magnetic force on the proton is: A) up B) down C) south D) west E) east

E) east

In the circuit shown, there will be a non-zero reading in galvanometer G: A) only just after S is closed B) only just after S is opened C) only while S is kept closed D) never E) only just after S is opened or closed

E) only just after S is opened or closed

A dielectric slab is slowly inserted between the plates of a parallel plate capacitor, while the potential difference between the plates is held constant by a battery. As it is being inserted: A) the capacitance, the potential difference between the plates, and the charge on the positive plate all increase B) the capacitance, the potential difference between the plates, and the charge on the positive plate all decrease C) the potential difference between the plates increases, the charge on the positive plate decreases, and the capacitance remains the same D) the capacitance and the charge on the positive plate decrease but the potential difference between the plates remains the same E) the capacitance and the charge on the plate increase but the potential difference between the plates remains the same

E) the capacitance and the charge on the plate increase but the potential difference between the plates remains the same

The primary of an ideal transformer has 100 turns and the secondary has 500 turns. Then: A) the power in the primary circuit is less than that in the secondary circuit B) the currents in the two circuits are the same C) the frequency in the secondary circuit is five times that in the primary current D) the primary voltage is five times the secondary voltage E) the primary current is five times the secondary current

E) the primary current is five times the secondary current

A magnetic field exists between the plates of a capacitor: A) always B) never C) only when the capacitor is fully charged D) only while the capacitor is being charged E) while the capacitor is being charged or discharged

E) while the capacitor is being charged or discharged

The switch S is initially at position a for a long time. It is then switched to position b. Describe what happens to the light bulb aw a function of time when the switch is flipped from a to b? A)The light bulb was on but goes off immediately B)The light bulb was off and stays off C)The light bulb was on but its brightness decreases with time and eventually goes off. D)The light bulb was on and stays on E)The light bulb was off. It lights up but the brightness decreases with time and eventually goes off.

E)The light bulb was off. It lights up but the brightness decreases with time and eventually goes off.

Two small spheres, each with mass m=3g and charge q, are suspended from a point by very light threads of length L=.22m. What is the charge on each sphere if the threads make an angle of 15 with the vertical? A. 0.79 uC B. 2.9 uC C. 75mC D. 6.3 uC E. .11uC

E. .11uC

An infinite plane of surface charge density omega=8nC/m^2 lies in the yz plane at origin and the second infinite plane of surface charge density omega=-8nC/m^2 lies in plane parallel to yz at x=4m. The electric field at x=5m is approximately: A. 226 N/C B. 339 N/C C. 904 N/C D. 452 N/C E. 0

E. 0

The electric field for rb1<r<rb2 is: A. -kQ/r^2 B. kQ/r^2 C. 2kQ/r^2 D. -2kQ/r^2 E. 0

E. 0

The diagrams show four possible orientations of an electric dipole in a uniform electric field E. Rank them according to the magnitude of the torque exerted on the dipole by the field, least to greatest. A. 1,2,3,4, B. 4,3,2,1 C. 3,1,2,4 D. 3, 2 and 4 tie, then 1 E. 1, 2 and 4 tie, then 3

E. 1, 2 and 4 tie, then 3

What happens to the electric potential energy of a positive charge when it is released from rest in a region of space where there is uniform electric field? A. it will remain constant because the electric field is uniform B. it will remain constant because the charge remains at rest C. it will increase because the charge will move in the direction of the electric field D. it will decrease because the charge will move in the opposite direction of the electric field E. It will decrease because the charge will move in direction of field.

E. It will decrease because the charge will move in direction of field.