NYC Review

1

Q1 An object on the end of a spring is oscillating in simple harmonic motion. If the amplitude of oscillation is doubled, how does this affect the oscillation period

T

and the object ’ s maximum speed

v

max ?

A.

T

and

v

max both double.

B.

T

remains the same and

v

max doubles.

C.

T

and

v

max both remain the same. D.

T

doubles and

v

max remains the same.

E.

T

remains the same and

v

max increases by a factor of .

Q2 This is an

x-t

graph for an object in simple harmonic motion.

At which of the following times does the object have the

most negative velocity v x

?

A.

t

=

T

/4 B.

t

=

T

/2 C.

t

= 3

T

/4 D.

t

=

T

Q3 This is an

x-t

graph for an object in simple harmonic motion.

At which of the following times does the object have the

most negative acceleration a x

?

A.

t

=

T

/4 B.

t

=

T

/2 C.

t

= 3

T

/4 D.

t

=

T

Q4 This is an motion.

x-t

graph for an object connected to a spring and moving in simple harmonic At which of the following times is the

potential energy

of the spring the greatest?

A.

t

=

T

/8 C.

t

= 3

T

/8 E. more than one of the above B.

t

=

T

/4 D.

t

=

T

/2

Q5 This is an motion.

x-t

graph for an object connected to a spring and moving in simple harmonic At which of the following times is the

kinetic energy

the object the greatest?

of A.

t

=

T

/8 C.

t

= 3

T

/8 E. more than one of the above B.

t

=

T

/4 D.

t

=

T

/2

Q6 To double the total energy of a mass-spring system oscillating in simple harmonic motion, the amplitude must increase by a factor of A. 4.

B. C. 2. D. E.

Q7 A simple pendulum consists of a point mass suspended by a massless, unstretchable string.

If the mass is doubled while the length of the string remains the same, the period of the pendulum A. becomes 4 times greater.

B. becomes twice as great. C. becomes greater by a factor of . D. remains unchanged.

E. decreases.

Q8 If you double the wavelength  happens to the wave speed

v

of a wave on a string, what and the wave frequency

f?

A.

v

is doubled and

f

is doubled. B.

v

is doubled and

f

is unchanged.

C.

v

is unchanged and

f

is halved. D.

v

is unchanged and

f

is doubled.

E.

v

is halved and

f

is unchanged.

Q9 The four strings of a musical instrument are all made of the same material and are under the same tension, but have different thicknesses. Waves travel A. fastest on the thickest string. B. fastest on the thinnest string. C. at the same speed on all strings.

D. not enough information given to decide

Q10 While a guitar string is vibrating, you gently touch the midpoint of the string to ensure that the string does not vibrate at that point.

The lowest-frequency standing wave that could be present on the string A. vibrates at the fundamental frequency.

B. vibrates at twice the fundamental frequency. C. vibrates at three times the fundamental frequency. D. vibrates at four times the fundamental frequency. E. not enough information given to decide

Q11 The air in an organ pipe is replaced by helium (which has a lower molar mass than air) at the same temperature. How does this affect the normal-mode

wavelengths

of the pipe? A. The normal-mode wavelengths are unaffected. B. The normal-mode wavelengths increase. C. The normal-mode wavelengths decrease.

D. The answer depends on whether the pipe is open or closed.

Q12 When you blow air into an open organ pipe, it produces a sound with a fundamental frequency of 440 Hz.

If you close one end of this pipe, the new fundamental frequency of the sound that emerges from the pipe is A. 110 Hz.

B. 220 Hz. C. 440 Hz.

D. 880 Hz.

E. 1760 Hz.

Q13 You hear a sound with a frequency of 256 Hz. The amplitude of the sound increases and decreases periodically: it takes 2 seconds for the sound to go from loud to soft and back to loud. This sound can be thought of as a sum of two waves with frequencies A. 256 Hz and 2 Hz. B. 254 Hz and 258 Hz. C. 255 Hz and 257 Hz.

D. 255.5 Hz and 256.5 Hz.

E. 255.75 Hz and 256.25 Hz.

Q14 On a day when there is no wind, you are moving toward a stationary source of sound waves. Compared to what you would hear if you were not moving, the sound that you hear has A. a higher frequency and a shorter wavelength. B. the same frequency and a shorter wavelength. C. a higher frequency and the same wavelength. D. the same frequency and the same wavelength.

Q15 On a day when there is no wind, you are at rest and a source of sound waves is moving toward you. Compared to what you would hear if the source were not moving, the sound that you hear has A. a higher frequency and a shorter wavelength. B. the same frequency and a shorter wavelength. C. a higher frequency and the same wavelength. D. the same frequency and the same wavelength.

Q16 When light passes from vacuum (index of refraction

n

into water (

n

= 1.333), = 1) A. the wavelength increases and the frequency is unchanged.

B. the wavelength decreases and the frequency is unchanged.

C. the wavelength is unchanged and the frequency increases.

D. the wavelength is unchanged and the frequency decreases.

E. both the wavelength and the frequency change.

Q17 Light passes from vacuum (index of refraction

n

water (

n

= 1.333).

= 1) into If the incident angle 

a

is in the range 0 ° < 

a

< 90 ° , A. the refracted angle is greater than the incident angle. B. the refracted angle is equal to the incident angle. C. the refracted angle is less than the incident angle. D. the answer depends on the specific value of 

a .

Q18 Light passes from a medium of index of refraction

n a

into a second medium of index of refraction

n b

. The angles of incidence and refraction are 

a

and 

b

respectively.

If

n a

<

n b

, 

a

> 

b

and the light speeds up as it enters the second medium. B. 

a

> 

b

and the light slows down as it enters the second medium. C. 

a

< 

b

and the light speeds up as it enters the second medium. D. 

a

< 

b

and the light slows down as it enters the second medium.

Q19 Light passes from a medium of index of refraction

n a

into a second medium of index of refraction

n b

. The critical angle for total internal reflection is  crit .

In order for total internal reflection to occur, what must be true about

n a

,

n b

, and the incident angle 

a

?

A.

n a

>

n b

and 

a

>  crit B.

n a

>

n b

and 

a

<  crit C.

n a

<

n b

and 

a

>  crit D.

n a

<

n b

and 

a

<  crit

Q20 Which of the following changes its focal length when it is immersed in water?

A. a concave mirror B. a convex mirror C. a diverging lens D. all of the above E. none of the above

Q21 A concave mirror with a radius of curvature of 20 cm has a focal length of A. 40 cm.

B. 20 cm.

C. 10 cm.

D. 5 cm.

E. answer depends on the index of refraction of the air around the mirror

Q22 An object is placed 4.0 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is A. real and larger than the object.

B. real and smaller than the object.

C. real and the same size as the object.

D. virtual and larger than the object.

E. virtual and smaller than the object.

Q23 An object is placed 0.5 m away from a concave mirror of focal length +1.0 m. The image formed by the mirror is A. real and larger than the object.

B. real and smaller than the object.

C. real and the same size as the object.

D. virtual and larger than the object.

E. virtual and smaller than the object.

Q24 An object is placed 2.0 m away from a convex mirror of focal length –1.0 m. The image formed by the mirror is A. real and larger than the object.

B. real and smaller than the object.

C. real and the same size as the object.

D. virtual and larger than the object.

E. virtual and smaller than the object.

Q25 An object in front of a converging lens, forming a real image

P

´

Q PQ

´

.

is placed If you use black paint to cover the lower half of the lens, A. only the object ’ s upper half will be visible in the image.

B. only the object ’ s lower half will be visible in the image.

C. only the object ’ s left-hand half will be visible in the image.

D. only the object ’ s right-hand half will be visible in the image.

E. the entire object will be visible in the image.

Q26 A thin lens has focal length

f

= –12 cm.

If an object 9 cm tall is placed 24 cm from the lens, what is the height of the image?

A. 27 cm tall B. 18 cm tall C. 9 cm tall D. 4.5 cm tall E. 3 cm tall

Q27 Which statement is true about a farsighted (hyperopic) eye?

A. The image point is in front of the retina; a converging eyeglass lens is used to correct this condition.

B. The image point is in front of the retina; a diverging eyeglass lens is used to correct this condition. C. The image point is behind the retina; a converging eyeglass lens is used to correct this condition.

D. The image point is behind the retina; a diverging eyeglass lens is used to correct this condition.

Q28 Two sources

S

1 and

S

2 oscillating in phase emit sinusoidal waves.

Point

P

is 7.3 wavelengths from source

S

1 from source

S

2 . As a result, at point

P

and 4.3 wavelengths there is A. constructive interference.

B. destructive interference.

C. neither constructive nor destructive interference.

D. not enough information given to decide.

Q29 In Young ’ s experiment, coherent light passing through two slits (

S

1 and

S

2 ) produces a pattern of dark and bright areas on a distant screen. If the wavelength of the light is increased, how does the pattern change? A. The bright areas move closer together.

B. The bright areas move farther apart.

C. The spacing between bright areas remains the same, but the color changes.

D. any of the above, depending on circumstances E. none of the above

Q30 In Young ’ s experiment, coherent light passing through two slits (

S

1 and

S

2 ) produces a pattern of dark and bright areas on a distant screen.

What is the difference between the distance from

S

1 the

m m

= +3 bright area and the distance from = +3 bright area?

S

2 to to the A. three wavelengths B. three half-wavelengths C. three quarter-wavelengths D. not enough information given to decide

Q31 An air wedge separates two glass plates as shown. Light of wavelength thickness

t

 strikes the upper plate at normal incidence. At a point where the air wedge has , you will see a bright fringe if

t

equals A.  /2.

C.   E. any of A., B., or C.

B. 3  /4.

D. either A. or C.

Q32 Light of wavelength  passes through a single slit of width

a

. The diffraction pattern is observed on a screen that is very far from from the slit. Which of the following will give the greatest

increase

in the angular width of the central diffraction maximum? A. Double the slit width

a

and double the wavelength   B. Double the slit width

a

and halve the wavelength  .

C. Halve the slit width

a

and double the wavelength   D. Halve the slit width

a

and halve the wavelength  

Q33 In Young ’ s experiment, coherent light passing through two slits separated by a distance

d

produces a pattern of dark and bright areas on a distant screen.

If instead you use 10 slits, each the same distance

d

its neighbour, how does the pattern change? from A. The bright areas move farther apart. B. The bright areas move closer together.

C. The spacing between bright areas remains the same, but the bright areas become narrower.

D. The spacing between bright areas remains the same, but the bright areas become broader.

Q34 In an experiment to demonstrate the photoelectric effect, you shine a beam of monochromatic blue light on a metal plate. As a result, electrons are emitted by the plate.

If you increase the intensity of the light but keep the color of the light the same, what happens?

A. More electrons are emitted per second.

B. The maximum kinetic energy of the emitted electrons increases.

C. both A. and B. D. neither A. nor B.

Q35 This graph in shows the stopping potential as a function of the frequency of light falling on a metal surface. If a different type of metal is used, A. the graph could have a different slope. B. the graph could intercept the horizontal axis at a different value.

C. both A. and B. D. neither A. nor B.

Q36 A certain atom has two energy levels whose energies differ by 2.5 eV.

In order for a photon to excite an electron from the lower energy level to the upper energy level, what must be true about the energy of the photon?

A. Its energy must be greater than or equal to 2.5 eV. B. Its energy must be exactly 2.5 eV.

C. Its energy must be less than or equal to 2.5 eV.

D. none of the above

Q37 In order for a proton to have the same momentum as an electron, A. the proton must have a shorter de Broglie wavelength than the electron.

B. the proton must have a longer de Broglie wavelength than the electron.

C. the proton must have the same de Broglie wavelength as the electron.

D. not enough information given to decide

Q38 A beam of electrons passes through a narrow slit. The electrons land on a distant screen, forming a diffraction pattern.

In order for a particular electron to land at the center of the diffraction pattern, it must pass A. through the center of the slit.

B. through the upper half of the slit.

C. through the lower half of the slit.

D. impossible to decide

Q39 The first five wave functions for a particle in a box are shown. The probability of finding the particle near

x

=

L

/2 is A. least for

n

= 1.

B. least for

n

= 2 and

n

= 4.

C. least for

n

= 5.

D. the same (and nonzero) for

n

= 1, 2, 3, 4, and 5.

E. zero for

n

= 1, 2, 3, 4, and 5.