Physics 104 Final

(T/F): If the maximum AC current increases to a new value that is twice as large as the original value, the new root-mean-square (rms) current also increases by a factor of 2 over the original value.

True

(T/F): In order to see a rainbow, the sun needs to be at your back.

True

(T/F): Rayleigh scattering predicts that the scattering of light is greater for light with short wavelengths.

True

(T/F): Refraction is due to light propagating at different speeds in different media.

True

(T/F): The angle of incidence equals the angle of reflection.

True

An object placed 20 cm in front of a diverging lens forms an image 4 cm in front of the lens. What is the focal length of the lens? A) -5.0 cm. B) 5.0 cm. C) -3.3 cm. D) 3.3 cm.

A) -5.0 cm.

The average diameter of the eye's pupil during the day is 4.0 mm. What is the minimum angle of separation for two 600 nm sources from which light passes through the pupil of the eye? A) 1.83x10^(-4) radians. B) 1.83x10^(-7) radians. C) 183 radians. D) 1.83x10^(-4) degrees.

A) 1.83x10^(-4) radians.

Two plane mirrors are placed 75 cm apart with their mirrored surfaces parallel and facing each other. If the mirrors are 10 cm wide, at what angle should a beam of light be incident at one end of one mirror so that it just strikes the far end of the other? A) 7.6 degrees. B) 2.3x10^(-2) degrees C) 7.6 radians D) 0.13 degrees E) 82.4 degrees

A) 7.6 degrees.

An induced EMF can be caused by (choose ALL that apply) A) a loop of wire that changes its orientation with respect to a constant magnetic field. B) moving a loop of wire along the direction of a constant magnetic field. C) a loop of wire that changes its size in a constant magnetic field. D) a loop of wire that changes its size, even if there is no magnetic field present E) a magnetic field that changes in time.

A) a loop of wire that changes its orientation with respect to a constant magnetic field. C) a loop of wire that changes its size in a constant magnetic field. E) a magnetic field that changes in time.

Images formed by plane mirrors (choose ALL answers that you think are correct) A) are virtual B) are inverted C) have the same heights as their associated objects. D) appear to be the same distance behind the mirror as the object is in front of the mirror. E) are real

A) are virtual C) have the same heights as their associated objects. D) appear to be the same distance behind the mirror as the object is in front of the mirror.

Destructive interference occurs when A) at least two light waves cancel each other at some location. B) light waves reinforce each other at some location. C) the energy in a light wave is destroyed. D) one light wave reflects from a surface.

A) at least two light waves cancel each other at some location.

An object placed in front of a concave spherical mirror A) can form different kinds of images depending on its distance from the mirror. B) forms a virtual image that is always smaller than the object. C) forms a virtual image that is always larger than the object. D) forms a real image that is always smaller than the object.

A) can form different kinds of images depending on its distance from the mirror.

To study wave interference, a student uses two speakers driven by the same sound wave of wavelength 0.3 m. If the distances from a point to the speakers differs by 0.45 m, the waves will A) interfere destructively. B) interfere constructively. C) interfere at some intermediate level. D) not interfere.

A) interfere destructively.

The focal length of a spherical mirror is equal to A) one-half the radius of curvature. B) twice the radius of curvature. C) one-quarter of the radius of curvature. D) the radius of curvature.

A) one-half the radius of curvature.

Light rays are A) representations of light that are perpendicular to wavefronts and point in the direction that the light wave propagates. B) really what light is. C) representations of light that are parallel to wavefronts and point in the direction that the light wave propagates. D) representations of light that are perpendicular to wavefronts and point in the direction opposite to that which the light wave propagates.

A) representations of light that are perpendicular to wavefronts and point in the direction that the light wave propagates.

Two identical waves destructively interfere when A) the crests of one wave occur at the same location as the troughs of the other. B) the troughs of one wave occur at the same location as the troughs of the other. C) the crests of one wave occur at the same location as the crests of the other. D) the waves move in opposite directions.

A) the crests of one wave occur at the same location as the troughs of the other.

Generators work because A) the rotating armature changes the area of the loop perpendicular to the magnetic field direction. B) the magnetic field pushes the armature around, generating current. C) the rotating armature causes centripetal forces that cause currents. D) the ends of the loop are connected to an external circuit.

A) the rotating armature changes the area of the loop perpendicular to the magnetic field direction.

Diffraction is most evident when A) the slit width is approximately equal to the wavelength of the incident wave. B) any wave is incident on any slit. C) the slit width is much smaller than the wavelength of the incident wave. D) the slit width is much larger than the wavelength of the incident wave.

A) the slit width is approximately equal to the wavelength of the incident wave. C) the slit width is much smaller than the wavelength of the incident wave.

During one cycle, the average AC voltage is A) zero. B) the maximum voltage. C) the maximum voltage minus the minimum voltage. D) one-half the maximum voltage.

A) zero.

A small dog sits at a distance of 2.0 m in front of a plane mirror. If the dog jumps away from the mirror with a speed of 0.75 m/s, how fast does the dog recede from its image? A) -0.75 m/s. B) 1.5 m/s. C) 0.75 m/s. D) 0 m/s.

B) 1.5 m/s.

A square loop of wire that encloses an area of 0.20 m^2 is in a uniform magnetic field of 0.10 T. What is the flux through the loop if its plane is at an angle of 62 degrees to the field? A) 9.4x10^(-3) B) 1.8x10^(-2) Wb C) 9.4x10^(-3) Wb D) 2.0x10^(-2) Wb

B) 1.8x10^(-2) Wb

Red light has a wavelength of 650 nm, and that of violet light is 430 nm. What is their frequency difference? A) 1.36x10^(6) Hz B) 2.36x10^(14) Hz C) 1.36x10^(15) Hz D) 220 Hz

B) 2.36x10^(14) Hz

The distance between lenses of a compound microscope is 20 cm. The focal length of the eyepiece is 20 mm, and the focal length of the objective is 0.5 cm. Find the total magnification of the microscope. Assume the near point distance is 20 cm. A) 40 B) 400 C) 500 D) 50

B) 400

A slit 0.010 mm wide is illuminated with blue light (lambda=500 nm). How wide is the central maximum formed on a screen 0.5 m from the slit? A) 1.25x10^{-2} m B) 5.0x10^{-2} m C) 5.0x10^{-2} D) 2.5x10^{-2} m

B) 5.0x10^{-2} m

A certain farsighted person has a near point of 75 cm. Which type of lens should an optometrist prescribe to see objects as close as 20 cm? A) A diverging lens with power=-6.33 D. B) A converging lens with power=+3.66 D. C) A diverging lens with power=-3.66 D. D) A converging lens with power=+6.33 D.

B) A converging lens with power=+3.66 D.

A ray of light leaves an object and passes through the focal point of a concave spherical mirror. After it reflects from the mirror, which of the following correctly describes its path? A) The ray travels perpendicular to the optical axis. B) The ray travels parallel to the optical axis. C) The ray retraces its original path, but moving in the opposite direction. D) The ray passes through the radius of curvature point.

B) The ray travels parallel to the optical axis.

How does the index of refraction in water for yellow light compare to that for green light? A) Yellow light has a higher index in water compared to green light. B) Yellow light has a lower index in water compared to green light. C) All visible light has the same index in water.

B) Yellow light has a lower index in water compared to green light.

According to the sign convention rules for the thin lens equation A) a positive positive focal length means the image is enlarged. B) a negative focal length means the image is virtual. C) a negative magnification means the image is virtual. D) a positive magnification means the image is reduced.

B) a negative focal length means the image is virtual.

An object placed in front of a convex spherical mirror A) forms a virtual image that is always larger than the object. B) forms a virtual image that is always smaller than the object. C) forms a real image that is always larger than the object. D) forms a real image that is always smaller than the object.

B) forms a virtual image that is always smaller than the object.

People who are near-sighted A) have near points at infinity. B) have far points closer than infinity. C) have far points at infinity. D) have near and far points at the same location.

B) have far points closer than infinity.

Ohm's law can be applied to AC circuits A) as long as you use the average voltage B) if the voltage and current used are rms values. C) no matter what voltage and current values you use. D) if the resistance used is an rms value.

B) if the voltage and current used are rms values.

To study wave interference, a student uses two speakers driven by the same sound wave of wavelength 0.3 m. If the distances from a point to the speakers differs by 0.45 m, the waves will A) interfere constructively. B) interfere destructively. C) interfere at some intermediate level. D) not interfere.

B) interfere destructively.

The total magnification of a compound microscope A) is determined only by the eyepiece lens. B) is equal to the product of the magnifications of the objective and eyepiece lenses. C) is determined only by the objective lens. D) is equal to the sum of the magnifications of the objective and eyepiece lenses.

B) is equal to the product of the magnifications of the objective and eyepiece lenses.

In a compound microscope, the image formed by the objective lens A) is on the same side of the objective as the object. B) is usually very near the focal point of the eyepiece lens. C) is real and forms at the eye. D) is usually very near the focal point of the objective lens.

B) is usually very near the focal point of the eyepiece lens.

Total internal reflection can occur A) only when light travels into a medium with a higher index of refraction. B) only when light travels into a medium with a lower index of refraction. C) only between silvered reflecting surfaces, like mirrors. D) at any surface between materials with different indices of refraction.

B) only when light travels into a medium with a lower index of refraction.

The image that is formed by a diverging lens of an object that is outside the focal point has a magnification that is A) negative and less than 1. B) positive and less than 1. C) negative and greater than 1. D) positive and greater than 1.

B) positive and less than 1.

Which set of colors below is ordered from most diffraction to least diffraction? A) blue, green, yellow, red. B) red, yellow, green, blue. C) red, green, yellow, blue. D) red, blue, yellow, green.

B) red, yellow, green, blue.

White light enters normal to the side of a glass prism. When the light emerges from an different, angled, side of the prism A) the red light exits with a larger refracted angle. B) the blue light exits with a larger refracted angle. C) all of the colors remain in a single ray, with the same refracted angle. D) the green light exits with a larger refracted angle.

B) the blue light exits with a larger refracted angle.

If a light ray leaves water and enters air, A) the light's speed decreases and the angle the ray makes with the normal in air is the same as the angle the ray makes with the normal in water. B) the light's speed increases and the angle the ray makes with the normal in air is larger than the angle the ray makes with the normal in water. C) the light's speed increases and the angle the ray makes with the normal in air is smaller than the angle the ray makes with the normal in water. D) the light's speed decreases and the angle the ray makes with the normal in air is larger than the angle the ray makes with the normal in water.

B) the light's speed increases and the angle the ray makes with the normal in air is larger than the angle the ray makes with the normal in water.

In the two-slit experiment, a bright interference fringe is produced on a screen when A) the two light waves travel distances that are different by any whole (integer) number of half-wavelengths. B) the two light waves travel distances that are different by any whole (integer) number of wavelengths. C) the two light waves travel distances that are different by any even number of wavelengths. D) the two light waves travel the same distance.

B) the two light waves travel distances that are different by any whole (integer) number of wavelengths.

If a loop of wire is stretched in a direction perpendicular to the direction of a constant, uniform magnetic field, A) then no induced current will run through the loop because the loop encloses a varying number of magnetic field lines. B) then an induced current will run through the loop because the loop encloses a varying number of magnetic field lines. C) then no induced current will run through the loop because the magnetic field is constant. D) then an induced current will run through the loop because the magnetic field is constant.

B) then an induced current will run through the loop because the loop encloses a varying number of magnetic field lines.

The image produced by a diverging lens is always A) virtual and enlarged. B) virtual and reduced. C) real and reduced. D) real and enlarged.

B) virtual and reduced.

Resolution describes A) the relative sizes of multiple objects. B) when multiple objects can be identified individually. C) the apparent roundness of multiple objects. D) how bright images of multiple objects appear.

B) when multiple objects can be identified individually.

If an object is 20 cm in front of a concave mirror that has a focal length of 80 cm, how tall will the image be? A) 1.5 times as tall as the object. B) As tall as the object. C) 1.3 times as tall as the object. D) 2.0 times as tall as the object.

C) 1.3 times as tall as the object.

An emergency AC generator operates at a rotation frequency of 120 Hz. If the output voltage is zero at t=0, when is it next zero? A) 3.13x10^(-3) s B) 1.67x10^(-2) s C) 4.17x10^(-3) s D) 8.33x10^(-3) s

C) 4.17x10^(-3) s

The armature of an AC generator has 200 turns, which are rectangular loops measuring 5 cm by 10 cm. The generator has a sinusoidal voltage output with an amplitude of 18 V. If the magnetic field of the generator is 300 mT, with what frequency does the armature turn? A) 9.55x10^(-7) Hz B) 60 Hz C) 9.55 Hz D) 6.0x10^(-6) Hz

C) 9.55 Hz

Two polarizers are set up so that their polarization directions are parallel and vertical. Which of the following describes light that has passed through both filters? A) The light is polarized in the horizontal direction. B) No light passes through both filters. C) The light is polarized in the vertical direction. D) The light is not polarized.

C) The light is polarized in the vertical direction.

If you place an object at the center of curvature of a spherical mirror, light from the object encounters A) a plane mirror. B) a convex mirror. C) a concave mirror. D) nothing listed here.

C) a concave mirror.

Electromagnetic radiation is caused by A) electric charges in motion. B) magnets in motion. C) accelerating electric charges. D) nuclear reactions.

C) accelerating electric charges.

To correct far-sightedness, a converging lens is used to A) create a virtual image at the far point. B) create a real image at the far point. C) create a virtual image at the near point. D) create a real image at the near point.

C) create a virtual image at the near point.

For a fixed screen distance, increasing the width of a single diffraction slit for light of a single wavelength A) does not affect the spacing between dark fringes. B) increases the spacing between dark fringes. C) decreases the spacing between dark fringes.

C) decreases the spacing between dark fringes.

A converging lens A) has a fixed focal length, but the sign is not important. B) has no fixed focal length. C) has a positive focal length. D) has a negative focal length.

C) has a positive focal length.

The speed of an electromagnetic wave A) is different for different wavelengths. B) depends on what creates it. C) is constant. D) is different for different frequencies.

C) is constant.

For a telescope, the fact that light enters the objective lens parallel to the optical axis A) means that the eyepiece image is formed at the focal point of the eyepiece lens. B) means that the objective image is formed on the same side of the lens as the object. C) means that the objective image is formed at the focal point of the objective lens. D) means that the eyepiece image is formed at the focal point of the objective lens.

C) means that the objective image is formed at the focal point of the objective lens.

If a light ray leaves water and enters air, A) the ray will be undeflected. B) the ray will bend towards the normal direction. C) the ray will bend away from the normal direction.

C) the ray will bend away from the normal direction.

If a light ray leaves air and enters water, A) the ray will bend away from the normal direction. B) the ray will be undeflected. C) the ray will bend towards the normal direction.

C) the ray will bend towards the normal direction.

A light wave travels in a medium with an index of refraction n1. It reflects from the surface of a medium with an index of refraction of n2. If n2 > n1, then A) the wave undergoes a 360-degree phase change. B) the wave undergoes no phase shift. C) the wave undergoes a 180-degree phase change. D) the wave undergoes a 90-degree phase change.

C) the wave undergoes a 180-degree phase change.

If white light is entering a slab of glass with an incident angle of zero relative to the normal, A) there is a dispersion of the wavelengths. B) the light is only reflected from the surface. C) there will be no dispersion because all wavelengths have zero refraction angles. D) there will be a dispersion of the reflected light.

C) there will be no dispersion because all wavelengths have zero refraction angles.

The magnetic flux through a loop of wire is maximum A) independent of the orientation of the magnetic field and loop. B) when the magnetic field direction is parallel to the plane of the loop. C) when the magnetic field direction is perpendicular to the plane of the loop. D) when the magnetic field direction is 45-degrees from the plane of the loop.

C) when the magnetic field direction is perpendicular to the plane of the loop.

Magnesium fluoride (n=1.38) is frequently used as a lens (n=1.50) coating to make nonreflecting lenses. What is the difference in the minimum film thickness required for maximum transmission of green light (lambda=520 nm) and yellow light (lambda=580 nm)? A) 1.50x10^{-8} m B) 1.50x10^{-8} C) 4.35x10^{-8} m D) 1.09x10^{-8} m

D) 1.09x10^{-8} m

An AC circuit with a resistance of 10-ohms has an effective current of 3.0 A. Find the peak voltage. A)42.4 B) 0.3 V C) 30 V D) 42.4 V

D) 42.4 V

Polarizer A is set up so that its polarization direction is vertical. Polarizer B is set up so that its polarization direction is 45 degrees from vertical. Which of the following describes light that has passed through both filters? A) No light passes through both polarizers. B) It is as intense as the original light and is polarized 45 degrees from vertical. C) It is less intense than the original light and is polarized vertically. D) It is less intense than the original light and is polarized 45 degrees from vertical.

D) It is less intense than the original light and is polarized 45 degrees from vertical.

During any complete cycle in which the initial EMF is zero, the EMF of an AC generator becomes zero again at A) no time ever. B) a time equal to one-quarter of the total period. C) a time equal to three-quarters of the total period. D) a time equal to one-half of the total period.

D) a time equal to one-half of the total period.

An interference pattern is produced by A) at least two sources of light. B) any one source of light. C) any one source of coherent light. D) at least two coherent sources of light.

D) at least two coherent sources of light.

An object placed in front of a convex spherical mirror A) forms a real image that is always larger than the object. B) forms a real image that is always smaller than the object. C) forms a virtual image that is always larger than the object. D) forms a virtual image that is always smaller than the object.

D) forms a virtual image that is always smaller than the object.

Two sources of light send waves through a single slit. The images are resolvable A) independent of the wavelength of the light. B) independent of the width of the slit. C) if the central bright spots of the individual diffraction patterns overlap. D) if the central bright spots of the individual diffraction patterns do not overlap.

D) if the central bright spots of the individual diffraction patterns do not overlap.

The polarization of light during reflection A) only occurs for water where n=1.33. B) only occurs at one specific angle. C) has nothing to do with the material doing the reflecting. D) is maximum at a specific angle that depends on the type of material.

D) is maximum at a specific angle that depends on the type of material.

A double convex lens A) makes parallel light rays diverge from the focal point. B) make diverging light rays converge at the focal point. C) makes converging light rays diverge at the focal point. D) makes parallel light rays converge at the focal point.

D) makes parallel light rays converge at the focal point.

The image formed by a converging lens of an object outside the focal point has a magnification that is A) positive. B) always greater than 1. C) always less than 1. D) negative.

D) negative.

In AC circuits, the voltage and current A) reach maximum and minimum values at times separated by 1/4 of a cycle. B) reach maximum and minimum values at times separated by 1/2 of a cycle. C) reach maximum and minimum values at times separated by 3/4 of a cycle. D) reach maximum and minimum values at the same points in time.

D) reach maximum and minimum values at the same points in time.

The electric and magnetic fields that make up a light wave A) reach maximum values at the same time and oscillate in the same direction. B) reach maximum values at different times but oscillate in perpendicular directions. C) reach maximum values at different times and oscillate in the same direction. D) reach maximum values at the same time but oscillate in perpendicular directions.

D) reach maximum values at the same time but oscillate in perpendicular directions.

In a motor, back EMF increases as A) the current in the loop increases. B) the external magnetic field gets stronger. C) the armature loop decreases its angular speed. D) the armature loop increases its angular speed.

D) the armature loop increases its angular speed.

Sunrises and sunsets appear to be orange-red because light travels through more atmosphere at those times and A) the blue light gets scattered into our line of sight. B) the red light gets scattered away from our line of sight. C) the red light gets scattered into our line of sight. D) the blue light gets scattered away from our line of sight.

D) the blue light gets scattered away from our line of sight.

For human vision, the near point is A) the point farthest from the eye at which objects can be seen clearly. B) also the focal point of the eye. C) the point right at the surface of the eye. D) the point closest to the eye at which objects can be seen clearly.

D) the point closest to the eye at which objects can be seen clearly.

Imagine you are boating on a lake during a warm summer day. Your polarized sunglasses dramatically cut down the glare from the lake's surface because A) the reflected light is significantly polarized in the horizontal direction and your sunglasses have horizontal polarized film. B) the reflected light is significantly polarized in the vertical direction and your sunglasses have horizontal polarized film. C) the reflected light is significantly polarized in the vertical direction and your sunglasses have vertical polarized film. D) the reflected light is significantly polarized in the horizontal direction and your sunglasses have vertical polarized film.

D) the reflected light is significantly polarized in the horizontal direction and your sunglasses have vertical polarized film.

(T/F): ALL rays that are parallel to the optical axis converge at the focal point for a concave spherical mirror.

False

(T/F): For a soap bubble, light reflecting from the inner surface of the bubble undergoes a phase-shift of 180-degrees.

False

(T/F): If the incident angle is less than the the critical angle, then you will have total internal reflection.

False

(T/F): Red light is refracted more than blue light.

False

(T/F): Since they diffract around normal, meter-sized objects, cell phone radio waves must be much shorter than one meter.

False

(T/F): The final image formed by two converging lenses is virtual.

False

(T/F): The image formed by a plane mirror is formed on the same side of the mirror as the object.

False

(T/F): To get destructive interference with a non-reflective coating on a glass surface, the light has to travel an extra distance in the coating equal to one quarter of a wavelength.

False

(T/F): Visible light is the only really useful type of electromagnetic radiation.

False

(T/F): A step-up transformer increases voltage while at the same time decreasing the current.

True

(T/F): For a soap bubble, light reflecting from the outer surface of the bubble undergoes a phase shift of 180-degrees.

True

(T/F): The angular magnification relates the angular size of an object at some location to the angular size of the image formed by a lens at the same location.

True

(T/F): The magnetic field due to an induced current points in a direction opposite to the direction of the field that caused the induced current.

True