Final Exam

A 10.0 V power supply is connected across a 150.0 ohm, resistor in a series with an 160.0 ohm resistor. What is the potential drop across the 150.0 ohm resistor? A. 4.8 V B. 5.2 V C. 11 V D. 9.4 V

A

A capacitor is charged to 2 mC when it is connected to a 12-V battery. How much energy is stored on the capacitor? A. 12 mJ B. 6mJ C. 144 mJ D. 24 mJ

A

A charged particle of mass 0.0040 kg is subjected to a 5.0-T magnetic field which acts at a right angle to its motion. If the particle moves in a circle of radius 0.20 m at a speed of 2.0 m/s, what is the magnitude of the charge on the particle? A. 0.0080 C B. 1300 C C. 130 C D. 0.00080 C

A

A convex mirror has a focal length of magnitude f. An object is placed in front of this mirror at a point of 2/3f from the face of the mirror. The image will appear A. upright and reduced B. inverted and reduced C. upright and enlarged D. behind the mirror E. inverted and enlarged

A

A small glass bead has been charged to 8.0 mC. What is the strength of the electric field 2.0 cm from the center of the bead? A. 1.8*10^5 N/C B. 1.4*10^-3 N/C C. 3.6*10^-6 N/C D. 3.6*10^3 N/C

A

A straight wire carries a current of 10 A at an angle of 30 degrees with respect to the direction of a uniform 0.30-T magnetic field. Find the magnitude of the magnetic force on a 0.50-m length of the wire. A. 0.75 N B. 6.0 N C. 3.0 N D. 1.5 N

A

An electron is moving to the right, as shown in the figure. Suddenly it encounters a uniform magnetic field pointing out of the page. Which one of the three paths shown will it follow in the field? A. path a B. path b C. path c

A

An ideal transformer consists of a 500-turn primary coil and a 2000-turn secondary turn coil. If the current in the secondary is 3.0 A, what is the current in the primary? A. 12 A B. 1.3 A C. 48 A D. 0.75 A

A

Each of the resistors shown in the figure has a resistance of 460.0 ohms. What is the equivalent resistance between points a and b of this combination? A. 1150 ohms B. 1380 ohms C. 1840 ohms D. 460.0 ohms

A

The focal length of the objective lens of a telescope is 75.0 cm, and the eyepiece has a focal length of 6.00 cm. What is the magnification of this telescope? A. 12.5 B. 0.0800 C. 0.645 D. 450 E. 200

A

The image formed in a plane mirror is A. at the same distance behind the mirror as the object is in front of the mirror. B. at a larger distance behind the mirror than the distance the object is in front of the mirror. C. a real image behind the mirror D. at the same distance in front of the mirror as the object is in front of the mirror E. at a shorter distance behind the mirror than the distance the object is in front of the mirror.

A

To maximize the magnification of a refracting telescope, what lenses should you choose? A. The objective lens should have a large focal length and the eyepiece should have a small focal length B. The objective lens should have a small focal length and the eyepiece should have a large focal length C. The objective lens should have a large focal length, but it doesn't matter what the focal length of the eyepiece is. D. The objective lens and eyepiece should both have large focal lengths. E. The objective lens and eyepiece should both have small focal lengths.

A

What do you buy from your electrical company? A. energy B. power C. potential D. current

A

What is the equivalent resistance in the circuit shown in the figure? A. 50 ohms B. 35 ohms C. 55 ohms D. 80 ohms

A

What is the wavelength used by a radio station that broadcasts at a frequency of 920 kHz? (c=3.00 * 10 ^8 m/s) A. 326 m B. 276 m C. 22.6 m D. 175 m E. 226 m

A

When a 7.00-mF air-filled capacitor has a charge of +/-50.0 mC on its plates, how much potential energy is stored in this capacitor? A. 179 mJ B. 149 mJ C. 143 mJ D. 159 mJ E. 169 mJ

A

When a light wave enters into a medium of different optical density, A. its speed and wavelength change. B. its speed, frequency, and wavelength change. C. its frequency and wavelength change. D. its speed and frequency change.

A

When unequal resistors are connected in parallel in a circuit, A. the potential drop is always the same across each resistor B. the power generated in each resistor is the same C. the largest resistance has the largest current through it D. the same current always runs through each resistor

A

A 4.0-cm-tall object is placed 60.0 cm from a diverging lens having a focal length of magnitude 30.0 cm. What is the nature and location of the image? A. A virtual image, 2.0 cm tall, 10 cm other side of the object B. A virtual image, 1.3 cm tall, 20.0 cm same side as the object C. A virtual image, 4.0 cm tall, 20 cm other side of the object D. A real image, 1.3 cm tall, 20.0 cm same side as the object E. A real image, 4.0 cm tall, 4.0 cm other side of the object

B

A bar magnet is oriented above a copper ring, as shown in the figure. The magnet is dropped and passes completely through the ring. As viewed from above, what is the direction of the current induced in the ring after the magnet has completely passed through the ring and is somewhat below it? A. There is no current in the ring. B. counterclockwise C. clockwise

B

A charged particle is injected into a uniform magnetic field such that its velocity vector is perpendicular to the magnetic field vector. The particle will A. follow a spiral path B. follow a circular C. move along a parabolic path D. move in a straight line

B

A coil lies flat on a level tabletop in a region where the magnetic filed vector points straight up. The magnetic field suddenly grows stronger. When viewed from above, what is the direction of the induced current in this coil as the field increases? A. clockwise initially, then counterclockwise before stopping B. clockwise C. counterclockwise D. There is no induced current in this coil

B

A convex spherical mirror has a focal length of magnitude 20 cm. If an object is placed 10 cm in front of the mirror on the mirror's axis, where is the image located? A. 6.7 cm in front of the mirror B. 6.7 cm behind the mirror C. 20 cm in front of the mirror D. 20 cm behind the mirror

B

A device obeying Ohm's law must have a resistance which is A. proportional to voltage B. constant C. proportional to current D. zero

B

A force of 6 N acts on a charge of 3 mC when is is placed in a uniform electric field. What is the magnitude of this electric field A. 18 N * mC B. 2 N * mC C. 0.5 mC / N D. None of the above

B

A negatively charged particle -Q is moving to the right, directly above the wire having a current I flowing to the right, as shown in the figure. In what direction is the magnetic force exerted on the particle due to the current? A. into the page B. upward C. out of the page D. downward E. The magnetic force is zero because the velocity is parallel to the current

B

A positive charge is moving to the right and experiences an upward magnetic force, as shown in the figure. In which direction must the magnetic field have a component? A. out of the page B. into the page C. to the right D. to the left E. upward

B

An image is 4.0 mm in front of a converging lens with a focal length of magnitude 5.0 mm. Where is the object for this image? A. 9.0 mm behind the lens B. 2.2 mm in front of the lens C. 20 mm in front of the lens D. 2.2 mm behind the lens

B

As more resistors are added in parallel across a constant voltage source, the power supplied by the source A. does not change B. increases C. increases for a time and then starts to decrease D. decreases

B

As shown in the figure, a wire and a 10 ohm resistor are used to form a circuit in the shape with dimensions 20 cm by 20 cm. A uniform but non-steady magnetic field is directed into the plane of the circuit. The magnitude of the magnetic field is steadily decreased from 1.20 T to 0.40 T in a time interval of 95 ms. What is the induced current in the circuit, and what is its direction through the resistor? A. 20 mA, from b to a B. 34 mA, from b to a C. 51 mA, from a to b D. 34 mA, from a to b E. 20 mA, from a to b

B

Electric Potential Energy per unit charge (J/C) is called A. electric field B. potential difference C. power D. electric force

B

If a object is placed between a convex lens and its focal point, the image formed is A. real and upright B. virtual and upright C. real and inverted D. virtual and inverted

B

Suppose you have two capacitors and want to use them to store the maximum amount of energy by connecting them across a voltage source. You should connect them A. in a series across the source B. in parallel across the source C. It doesn't matter because the stored energy is the same either way

B

A 15 ohm resistor is connected parallel across a 30 ohm resistor. If this combination is now connected in series with a 9.0 V battery and a 20 ohm resistor, what is the current through the 15 ohm resistor? A. 0.10 A B. 0.26 A C. 0.20 A D. 0.13 A

C

A 3.0-mF capacitor and 5.0-mF capacitor are connected in a series across an 8.0-V potential source. What is the potential difference across the 3.0-mF capacitor? A. 0 V B. 2.7 V C. 5.0 V D. 3.6 V E. 8.0 V

C

A 3.0-mF, a 12-mF, and a 29-mF capacitor are connected in parallel. How much capacitance would a single capacitor need to have to replace the three capacitors? A. 3.0 mF B. 12 mF C. 44 mF D. 29 mF

C

A 4.0-mF and a 14.0-mF capacitor are connected in series, and the series arrangement is connected to a 24.0-mF capacitor. How much capacitance would a single capacitor need to replace this combination of three capacitors? A. 17 mF B. 32 mF C. 27 mF D. 13 mF

C

A 500-W device is connected to a 100-V power source. What current flows through this source? A. 0.2 A B. 50000 A C. 5 A D. None of the above

C

A beam of light in air enters a glass slab with an index of refraction of 1.80 at an angle of incidence of 30.0 degrees. What is the angle of refraction? A. 14.9 B. 51.8 C. 16.1 D. 30.0 E. 47.5

C

A certain 20-A circuit breaker trips when the current in it equals 20 A. What is the maximum number of 100-W light bulbs you can connect in parallel in 120-V circuit without tripping this circuit breaker? A. 17 B. 11 C. 23 D. 27

C

A charged particle moves with its velocity perpendicular to a magnetic field. The filed acts to change the particle's A. mass B. charge C. velocity D. energy

C

A circular coil of 40 turns and radius 9.0 cm is placed with its plane oriented at 90 degrees to a uniform magnetic field of 0.10 T. The field is now increased at a steady rate, reaching a value of 0.60 T after 7.0 seconds. What emf is induced in the coil? A. 0.17 V B. 0.096 V C. 0.073 V D. 0.12 V E. 0.14 V

C

A conduction rod whose length is l=25 cm is placed on a U-shaped metal wire that is connected to a light bulb having a resistance of 8.0 ohms as shown in the figure. The wire and the rod are in the plane of the page. A constant uniform magnetic field of strength 0.40 T is applied perpendicular to and out of the paper. An external applied force moves the rod to the left with a constant speed of 12 m/s. What are the magnitude and direction of the induced current in the circuit? A. 34 mA counterclockwise B. 34 mA clockwise C. 150 mA counterclockwise D. 100 mA clockwise E. 150 mA clockwise

C

A glass rod is rubbed with a piece of silk. During the process the glass rod acquires a positive charge and the silk A. acquires a positive charge also B. remains neutral C. acquires a negative charge D. could be either positively charged or negatively charged

C

A proton is projected with a velocity of 7.0 km/s into field of 0.60 T perpendicular to the motion of the proton. What is the magnitude of the magnetic force that acts on the proton? (e=1.60*10^-19 C) A. 3.4 * 10 ^ -16 N B. 0 N C. 6.7 * 10 ^ -16 N D. 13 * 10 ^ -16 N E. 4.2 * 10 ^ -16 N

C

An electronic component with a 6.0 ohm resistor is rated for use at power levels not exceeding 14 W. How much current can safely flow through the component? A. 0.62 A B. 84 A C. 1.53 A D. 0.43 A

C

Breaking a bar magnet in half will produce A. a single north pole B. a single south pole C. two bar magnets D. one north and one south pole

C

Faraday's law of induction states that the EMF induced in a loop of wire is proportional to A. the magnetic flux times the loop's area B. the magnetic flux C. change in the magnetic flux D. current divided by time

C

For the circuit shown in the figure current I1 flows downward on the far left, current I2 flows upward through the 4 ohm resistor, and current I3 flows upward on the far right side. What is the correct loop rule for the outermost loop? A. 0=-7I+8I3+21 B. 0=+7I+8I3+21 C. 0=-7I-8I3+21 D. 0=-7I+8I3-21

C

How much current will be flowing through a 61.0-m length of copper wire with 6.1 mm if it is connected to a source supplying 34.0 V? The resistivity of the metal is 1.68 x 10^-8 ohm*m. A. 95 nA B. 20 x 10^8 A C. 3900 A D. 2300 A

C

Identical ideal batteries are connected in different arrangements to the same light bulb, as shown in the figure. For which arrangement will the bulb shine the brightest? A. 1 battery B. 2 batteries connected with long wire C. 2 batteries connected with short wire

C

If unpolarized light of intensity I0 passes through an ideal polarizer, what is the intensity of the emerging light? A. I0/4 B. I0 C. I0/2 D. I0/16

C

It takes 10 J of energy to move 2 C of charge from point A to point B. What is the potential difference between point A and B? A. 0.2 V B. 20 V C. 5 V D. None of the above

C

Lenz's law is a consequence of the law conservation of A. charge B. mass C. energy D. momentum

C

Two electrons are 27.0 mm apart at closest approach. What is the magnitude of the maximum electric force that they exert on each other? A. 3.2*10^-27 N B. 1.2*10^10 N C. 3.2*10^-25 N D. 1.2 N

C

What charge accumulates on the plates of a 6.0-mF air-filled capacitor when it is charged until the potential difference across its plates is 40 V? A. 180 mC B. 60 mC C. 240 mC D. 120 mC

C

What current is flowing in a wire if 0.47 C of charge pass a point in the wire in 0.20 s? A. 0.47 A B. 0.20 A C. 2.4 A D. 0.094 A

C

Which of the following will increase the capacitance of a parallel-plate capacitor? A. an increase in potential difference between the plates B. a decrease in the plate area and an increase in the plate separation C. an increase in the plate area and a decrease in the plate separation D. an increase in the charge on the plates E. a decrease in the potential difference between the plates

C

A 3.0-mC point charge and a 10.0-mC point charge are initially extremely far apart. How much work does it take to bring the 3.0-mC point charge to a position 6.0 mm frin tge 10.0-mC point charge? A. 90 J B. 30 J C. 7.5 J D. 45 J

D

A drawing is placed 40 cm in front of a thin lens. If a virtual image forms at a distance of 50 cm from the lens, on the same side as the drawing, what is the focal length of the lens? A. +45 cm B. 75 cm C. -45 cm D. 200 cm E. 90 cm

D

A person jogs toward a plane mirror at a speed of 2 m/s. How fast is he approaching his image in the mirror? A. 1 m/s B. 15 m/s C. 3 m/s D. 4 m/s E. 2 m/s

D

A ray of white light, incident upon a glass prism, is dispersed into its various color components. Which one of the following colors experiences the greatest angle of refraction? A. green B. red C. orange D. violet

D

A transformer is a device that operates A. to increase power B. only on DC C. on either DC or AC D. only on AC

D

A woman's face is 20 cm in front of a concave makeup mirror having a focal length of magnitude 30 cm. How large is the image of her face? A. four times as large as her face B. of the same size as her face C. twice as large as her face D. three times as large as her face E. half as large as her face

D

An electron, free to move when placed in an electric field, moves A. perpendicular to the field lines B. unaffected by the field C. along the field lines, in the field direction D. along the field lines, opposite the filed

D

Copper wire #1 has a length L and a radius b. Copper wire #2 has a length 2L and a radius 2b. Which statement about the resistance across the ends of the wires is true? A. The resistance of wire #1 is half that of wire #2 B. The resistance of wire #1 is four times higher than that of wire #2 C. The resistance of wire #1 is equal to that of wire #2 D. The resistance of wire #1 is twice as high as that of wire #2

D

How much current must pass through a 400-turn ideal solenoid that is 4.0 cm long to generate a 1.0-T magnetic field at the center? (m0= 4pi * 10 ^ -7 T*m/A) A. 22 A B. 13 A C. 0.013 A D. 80 A E. 40 A

D

How much does it cost to operate a 25-W soldering iron for 8.0 hours if energy costs 8.0 cents per kWh? A. $1.50 B. 25 cents C. 16 cents D. 1.6 cents

D

If a charge generator builds a negative static charge of -13.00 mC, how many electrons are transferred to it during this process. A. 13.0 B. 81.3 C. 2.08*10^-18 D. 8.13*10^13

D

The Law of Reflection states that "the angle of incidence... A. may be greater than, less than, or equal to the angle of reflection". B. is always greater than the angle of refraction". C. is always less than the angle of refraction". D. must be equal the angle of reflection".

D

Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are doubled and their separation is also doubled, what happens to the electrical force that each charge exerts on the other one? A. It increases by a factor of 2 B. It increases by a factor of the square root of 2 C. It increases by a factor of 4 D. It remains the same E. It is reduced by a factor of the square root of 2

D

Two tiny particles having charges +60.0 mC and -12.0 mC are separated by a distance of 20.0 cm. What are the magnitude and direction of electric filed midwat between these two charges? A. 64.7 10*^5 N/C directed towards the positive charge B. 64.7 10*^6 N/C directed towards the positive charge C. 64.7 10*^5 N/C directed towards the negative charge D. 64.7 10*^6 N/C directed towards the negative charge E. 64.7 10*^4 N/C directed towards the negative charge

D

What is the power of a lens that has a focal length of -40 cm and a width of 2.0 cm? A. +4.0 diopters B. -0.50 diopters C. +2.5 diopters D. -2.5 diopters E. -50 diopters

D

What is the voltage drop across a 6.0 ohm resistor if the current through it is 6.0 A? A. 1.0 V B. 240 V C. 12 V D. 36 V

D

When the current through a resistor is increased by a factor of 4, the power dissipated by the resistor A. decreases by a factor of 16 B. increases by a factor of 2 C. decreases by a factor of 4 D. increases by a factor of 16 E. increases by a factor of 4

D

A multiloop circuit is shown in the figure. What is the correct junction rule for junction "g"? A. 0=-I2-I3+I4 B. 0=I2+I3-I4 C. 0=-I2-I3-I4 D. 0=I2+I3+I4 E. 0=I2-I3+I4

E

A negatively-charged rod is brought close to (but does not touch) two neutral spheres that are in contact with each other but insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres. A. Both spheres become negative B. The sphere near the charged rod becomes negative and the other one becomes positive C. Both spheres become positive D. The spheres do not get any charge E. The sphere near the charged rod becomes positive and the other one becomes negative

E

An object is placed 16 cm from a concave lens having a focal length of magnitude 20 cm. What is the magnification? A. -0.56 B. -0.22 C. -0.32 D. 0.22 E. 0.56

E

An object that is 10.0 cm tall is placed 33.0 cm in front of a concave mirror of focal length 16.5 cm. How tall is the image? A. 20.0 cm B. 5.0 cm C. 2.5 cm D. 7.5 cm E. 10.0 cm

E

Nearsightedness is usually corrected with A. cylindrical lenses B. concave mirrors C. convex mirrors D. converging lens E. diverging lens

E