Physics 205: General Physics II

Final Exam version 1

# Name _________________________Date______________

Instructions: You are allowed only your calculator and formula cards for this exam. You have 2 hours to complete the exam.  Answer All of the following questions .

# 1. When the separation between two identical charged particles is increased by a factor of five the magnitude of the force___________________(increases/decreases) by a factor of

___ 1.two                                Choose ONE

___ 2. three

___ 3.five

___ 4.twenty five

___ 5.ten

2. Six identical resistors are connected first in parallel and then in series.

Which combination has the greater resistance?

___ 1. the set in parallel

___ 2. the set in series

___ 3. the two combinations have the same resistance

___ 4. walrus

3. Two test charges are brought separately into the vicinity of a charge +Q.   First, test charge +q is brought to point A , a  distance r from +Q.  Next, +q is removed and a test charge +2q is brought to point B a distance 2r from +Q.

Compared with the electrostatic Force of the charge at A, that of the charge at B is

___1. greater.

___2. smaller.

___3. the same.

4. In order to increase the electrical energy stored in a parallel-plate capacitor when

an electric potential is applied, we should

___ 1. increase the surface area of the plates.

___ 2. increase the separation between the plates.

___ 3. Carry it to the top of a tall building

___ 4. all of the above

___ 5. two of the above

___ 6. none of the above

5.      A 12 volt battery is connected to a series circuit with 110 W equivalent resistance.  If the circuit is closed for 90 seconds,  what is the total charge that passed through the circuit? ( remember how current is defined !)

___1. 0.11 coulombs

___2. 9.81 coulombs

___3. 9.16 coulombs

___4. 0.0012 coulombs

6. The magnetic domains in a non-magnetized piece of iron are characterized by which orientation?

___ 1. Parallel to the magnetic axis.

___ 2. Antiparallel to the magnetic axis.

___ 3. Perpendicular to the magnetic axis.

___ 4. Random with the vector sum magnetization equaling zero.

7.  An electrical current  is applied across a solenoid (coil of wire).  As a result of the current a

___1. magnetic field is produced in the direction of the current.

___2.  magnetic field is produced perpendicular to the direction of the current.

___3.  Only an electric field is observed.

___4. None of the above.

8.  The force on a charged particle created by its motion in a magnetic field is at maximum at what angle between the particle's velocity and the field?

___1. zero

___2. 33.33.

___3. 45.

___4  90.00

9. The force exerted on a charged particle in a uniform external magnetic field is directly proportional to which of the following.

___1. velocity

___2. Field strength.

___3. both.

___4  neither

10.  The path of  a charged particle moving parallel to a uniform magnetic field will be ..

___1. A straight line

___2. A circle.

___3. A triangle.

___4  what--everrr

11.  You stand two meters away from a plane mirror. How far is it from you to your image?

___ 1. 2m

___ 2. 4m

___ 3. 6m

___ 4. 8m

13.  A 3cm tall object is placed along the principal axis of a thin biconvex lens with focal length 30 cm.  If  the object distance is 40cm, what is the image distance and image height?

___ 1. 17 cm away and 7 cm high.

___ 2  120 cm away and 9 cm high.

___ 3. No image formed

___4   120 cm 1 cm high.

14.Which of the following describes the image that forms for a convex lens when the object distance is less than the focal length of the lens?

___1. Inverted, enlarged and real.

___2.  Upright, enlarged and virtual.

___3.  Upright, smaller and virtual.

___4. Inverted, smaller and real.

15. Which of the following describes the image that forms for a convex lens when the object distance is greater than the focal length of the lens?

___1. Inverted, enlarged and real.

___2. Inverted, smaller and real..

___3.  Upright, smaller and virtual.

___4. Upright, enlarged and virtual

16.  A beam of white light is incident upon a prism, and dispersed into its various components.  Which color will show the greatest angle of deviation

___1. orange

___2. violet.

___3. red.

___4  green

___5 yellow

___6 blue

17.              Water has an index of refraction of 1.333.  What is the speed of light in water?

___1. 4x10­8 m/s

___2. 2.25x10­8 m/s

___3. 4.46x10­8 m/s.

___4  1.46x10­8 m/s

18.  Rank each  form of  electromagnetic radiation according to energy from highest to lowest.

___x-rays

___microwaves

___ultraviolet light

___blue visible light

___infrared light

19. You are at rest on a platform at a railroad station. A train approaches the platform

blowing its whistle. As the train approaches you, the pitch of the whistle

___ 1. Is higher relative to a person on the train.

___ 2. Is lower relative to a person on the train.

___ 3. Oscillates both high and low.

___ 4. depends on the amplitude of the sound.

20. For the following arrangements of  resistors shown, what is the equivalent resistance between points A and B?

21.    For the following orientations of velocity and magnetic field, determine the direction

of the force.

Part 2

23.  Three point charges lie at the corners of an equilateral triangle, 1 cm on each side.  The charges at the corners are +2 , +4 and +6 microcoulombs respectively.  If the +2 microcoulomb charge is free to move, and the others are fixed in space, what will be the magnitude and direction of the force encountered by the 2 microcoulomb charged body?

Part 2

24.An electron is accelerated in a TV cathode ray  tube through a potential difference of

50,000 volts.  What is the electric field the electron encounters if the plate separation is 3 cm?  What is the magnitude of the force felt by the electron?  If the electron mass is 9.11x 10 –31 kilograms, what is the magnitude of the acceleration?

Determine the time required for the electron to traverse 3cm.

Part 2

25. Two uniformly charged spheres are fastened to and electrically insulated from

frictionless pucks on an air hockey table. The charge on sphere 2 is three times the charge on sphere 1 which has 5 microcoulombs charge. They are separated by a distance of 0.3 meters.  What is the force encountered by each of  the charged spheres?  Is it attractive or repulsive? If the first sphere is twice as massive as the second, its acceleration would be what?

BONUS:

26.  For the following circuit R1 =R2, The current leaving the battery, I = 4A, and the voltage,  V=12 volts.  Determine the resistance of R1 and R2 and Req ..  Now R2 is placed in an ice water bath, at 0 degrees C, while R1 remains at room temperature, 25 degrees C.  R1 at room temperature is =  12 R2. ( R2 decreases to R1/12).  What is R eq  for the whole circuit when R2 is in the ice bath?