Physics Final
A standing wave of frequency 5 Hertz is set up on a string 2 meters long with nodes at both ends and in the center, as shown above The fundamental frequency of vibration of the string is
2.5 Hz
The diagram above shows an isolated, positive charge Q. Point B is twice as far away from Q as point A. The ratio of the electric field strength at point A to the electric field strength at point B is
4 to 1
Which of the following is true about the net force on an uncharged conducting sphere in a uniform electric field?
It is zero.
An object is placed at the focal point in front of a concave mirror. The image is located:
No image is formed
An object is placed at the center of the curvature in front of a concave mirror. The image is located
The distance d=R
You stand a certain distance away from a speaker and you hear a certain intensity of sound. If you double your distance from the speaker, what happens to the sound intensity at your new position?
drops to 1/4 its original value
A concave mirror with a radius of curvature of 1.0 m is used to collect light from a distant star. The distance between the mirror and the image of the star is most nearly
0.50 m
Two parallel conducting plates are connected to a constant voltage source. The magnitude of the electric field between the plates is 2,000 N/C. If the voltage is doubled and the distance between the plates is reduced to 1/5 the original distance, the magnitude of the new electric field is
20,000 N/C
Two concentric circular loops of radii b and 2b, made of the same type of wire, lie in the plane of the page. The total resistance of the wire loop of radius b is R. What is the resistance of the wire loop of radius 2b?
2R
A physics student places an object 6.0 cm from a converging tens of focal length 9.0 cm. What is the magnitude of the magnification of the image produced?
3.0
A tuning fork is used to create attending waves in a tube open at the top and partially filled with water. A resonance is heard when the water level is at a certain height. The next resonance is heard when the water level has been lowered by 0.5 m. If the speed of sound is equal to 340 m/s, the frequency of the tuning fork is
340 Hz
Assume that the voltage of the battery is 9 V and that the three resistors are identical. What is the potential difference across each resistor?
3v
the product of 2 amperes x 2 volts x 2 seconds is equal to
8 joules
A certain coffeepot draws 4.0 A of current when it is operated on 120 V household lines. If electrical energy costs 10 cents per kilowatt‑hour, how much does it cost to operate the coffeepot for 2 hours?
8.0 cents
Kirchhoff's loop rule for circuit analysis is an expression of which of the following?
Conservation of energy
Which of the following will cause the electrical resistance of certain materials known as superconductors to suddenly decrease to essentially zero?
Cooling the material below a certain threshold temperature
The worst thing you can do for the health of a green-leafed plant is to illuminate it with only
Green light
Points P and Q are connected to a battery of fixed voltage. As more resistors R are added to the parallel circuit, what happens to the total current in the circuit?
Increases
Two cables can be used to wire a circuit. Cable A has a lower resistivity, a larger diameter, and a different length than cable B. Which cable should be used to minimize heat loss if the same current is maintained in either cable?
It cannot be determined without knowing the length of each cable
A wire of resistance R is stretched uniformly (keeping its volume constant) until it is twice its original length. What happens to the resistance?
It increases by a factor of 2
If three resistors with unequal resistance are connected in parallel in a DC circuit, which of the following is true of the total resistance?
It is lower than the value of the lowest resistance.
One end of a horizontal string is fixed to a wall. A transverse wave pulse is generated at the other end, moves toward the wall. Properties of the reflected pulse include which of the following?
It is on the opposite side of the string from the incident pulse
The hollow metal sphere shown above is positively charged. Point C is the center of the sphere and point P is any other point within the sphere. Which of the following is true of the electric field at these points?
It is zero at both points
The hollow metal sphere shown above is positively charged. Point C is the center of the sphere and point P is any other point within the sphere. Which of the following is true of the electric field at these points
It is zero at both points.
Two lightbulbs in the circuit are identical. When the switch is closed what happens?
Nothing Changes
An object is placed at a distance of 1.5¦ from a converging lens of focal length ¦, as shown above. What type of image is formed and what is its size relative to the object (Type, Size)?
Real, Larger
A standing wave pattern is created on a guitar string as a person tunes the guitar by changing the tension in the string. Which of the following properties of the waves on the string will change as a result of adjusting only the tension in the string?
Speed of the traveling wave that creates the pattern and Frequency of the standing wave
Conducting sphere X is initially uncharged. Conducting sphere Y has twice the diameter of sphere X and initially has charge q. If the spheres are connected by a long thin wire, which of the following is true once equilibrium has been reached?
Spheres X and Y have the same potential
Two lightbulbs operate at 120 V, but one has a power rating of 25 W while the other has a power rating of 100 W. Which one has the greater resistance?
The 100W bulb
Two parallel conducting plates, separated by a distance d, are connected to a battery of emf. Which of the following is correct if the plate separation is doubled while the battery remains connected?
The capacitance is unchanged
In the Doppler effect for sound waves, factors that affect the frequency that the observer hears include which of the following?
The speed of the source and The speed of the observer
If the separation between the plates of an isolated charged parallel-plate capacitor is increased slightly, which of the following also increases?
The stored electrostatic energy
Which of the following is characteristic of both sound and light waves?
They give rise to interference effects.
Two wires, A and B, are made of the same metal and have equal length, but the resistance of wire A is four times the resistance of wire B. How do their diameters compare?
dA=1/2dB
As shown above, a beam of white light is separated into separate colors when it passes through a glass prism. Red light is refracted through a smaller angle than violet light because red light has a
faster speed in glass than violet light
Two lightbulbs A and B are connected in a series to a constant voltage source. when wire is connected across B, bulb A will
grow brighter then before
Two space heaters in your living room are operated at 120 V. Heater 1 has twice the resistance of heater 2. Which one will give off more heat?
heater 2
If the object distance for a converging thin lens is more than twice the focal length of the lens, the image is
located at a distance between f and 2f from the lens
An electron e and a proton p are simultaneously released from rest in a uniform electric field E, as shown above. Assume that the particles are sufficiently far apart so that the only force acting on each particle after it is released is that due to the electric field. At a later time when the particles are still in the field, the electron and the proton will have the same
magnitude of force acting on them
The color of an object is the same as the light that is
reflected
When light passes from air into water, the frequency of the light remains the same. What happens to the speed and the wavelength of light as it crosses the boundary in going from air into water?
speed decreases, wavelength decreases
An object is placed in front of a converging thin lens at a distance from the center of the lens equal to half the focal length. Compared to the object, the image is
upright and larger