Q&A Hero

Physic

Q: In general, an insulator will have a low resistance to current flow.
Q: An alternate equation for power in an electric circuit is P = IR.
Q: In a parallel circuit with three resistors all the same size, the current flow though each leg of the circuit will be equal.
Q: In a circuit connected to a battery, the current flows from negative pole toward the positive pole of the battery.
Q: If two heaters are connected in parallel across the 120 volt source, the current drawn from the source is 10 amperes.
Q: If two heaters are connected in parallel across the 120 volt source, the total power drawn from the source increases to 2400 watts.
Q: The resistance of the heater is 10 ohms.
Q: NARRBEGIN: Heater 1200 wattsA heater is rated at 1200 watts for a 120 volt source.NARRENDThe current drawn by the heater is 10 amperes.
Q: The energy used by a 100 watt light bulb in 1 hour is 100 kilowatt-hours.
Q: The energy used by a 100 watt light bulb in 1 hour is 360,000 joules
Q: If two slide projectors are connected in series across the same 120 volt source, the current drawn from the source remains at 6 amperes.
Q: If two slide projectors are connected in parallel across the same 120 volt source, the current drawn from the source remains at 6 amperes.
Q: The power consumed by the light bulb is 20 watts.
Q: NARRBEGIN: Lightbulb slide projectorA light bulb used in a slide projector draws a current of 6 amperes when operating on 120 volts.NARRENDThe resistance of the light bulb is 20 ohms.
Q: A light bulb designed for use with AC would still work if hooked up to DC of the proper voltage.
Q: In a parallel circuit, the size of the current flowing through each device may be different.
Q: If an electric toaster operating on 120 volts draws a current of 6 amperes, the resistance of the toaster is 20 ohms.
Q: A battery stores electric charge in the same way that a bottle stores water.
Q: A battery operating a large flashlight produces a current of 2 amperes in a light bulb that has a resistance of 4 ohms. The voltage of the battery is 2 volts.
Q: If the current drawn from a 12 volt car battery is 100 amperes when it is short circuited with a wire, the resistance of the wire is 0.12 ohms.
Q: An electrostatic precipitator uses an electric field to remove smoke from the air.
Q: Semiconductor technology has been the basis for many new electronic devices.
Q: Solids that are good conductors of heat tend also to be good conductors of electricity.
Q: The resistance of a wire does not change when its temperature changes.
Q: If the diameter of a wire increases, its resistance decreases.
Q: If the length of a wire increases, its resistance decreases.
Q: The resistance of a conducting material depends on its composition, length, diameter, and temperature.
Q: Two charged bodies separated by a distance d exert a repulsive electrical force on each other. The signs of the charges on the two bodies are + and ".
Q: Two charged bodies separated by a distance d exert an electrical force on each other. The distance d is doubled. The electrical force on each body is now 1/2 of the original force.
Q: Larger batteries have higher output voltages.
Q: Voltage is the force on a charged object divided by the charge on the object.
Q: Current is the opposition to the flow of charge.
Q: Voltage can also be called potential.
Q: Voltage is a measure of the energy per unit charge supplied by a battery.
Q: Superconductivity is lost when a certain critical temperature is exceeded.
Q: Electrons are negatively charged.
Q: The SI unit of electric charge is e, the charge on the electron.
Q: Current is the rate of flow of electric charge.
Q: An object that has zero resistance is a semiconductor.
Q: All three types of particles found in atoms are electrically charged.
Q: An atom with fewer electrons than protons is a negative ion.
Q: NARRBEGIN: Source emits soundA source emits sound at a fixed constant frequency f.NARRENDIf the source moves away from you, the frequency you hear isa. the same as f b. higher than f c. lower than fd. unrelated to f
Q: You shout at a cliff, and hear your echo in 2 seconds. If the speed of sound in the air is 340 m/s, the distance of the cliff from you isa. 85 mb. 170 mc. 340 md. 680 me. none of the above
Q: A wave moves in a rope with a certain wavelength. A second wave is made to move in the same rope with twice the wavelength of the first wave. The frequency of the second wave is _______________ the frequency of the first wave.a. 1/2 b. the same as c. 2 timesd. unrelated to
Q: NARRBEGIN: Snapshot of 4 differentThe figure shows a "˜snapshot" of four different waves in identical ropes stretched with the same force.NARRENDThe wave where the speed is greatest isa. Ib. IIc. IIId. IVe. all of the above
Q: You have two identical ropes stretched with the same force between two different sets of posts. The second rope is twice as long as the first rope. The velocity of a wave in the second rope is ____________ the velocity of a wave in the first rope.a. 1/2b. timesc. the same asd. timese. 2 times
Q: You have two ropes of the same length. The mass of the second rope is twice the mass of the first rope. The velocity of a wave in the second rope is ___________ the velocity of a wave in the first rope. a. 1/2 b. times c. the same as d. times e. 2 times
Q: NARRBEGIN: Force F stretches a ropeWhen a force F stretches a rope of mass per unit length r, the velocity of a wave in the rope is given byNARRENDYou pull on a rope with a certain force, and a wave travels in the rope with a certain velocity. If you double your force, the velocity of a wave in the rope is now ____________ the original velocity.a. 1/2b. timesc. the same asd. timese. 2 times
Q: Which of the following can change the frequency of a wave?a. interferenceb. the Doppler effectc. diffractiond. all of the above
Q: Two sound waves traveling through the air have different frequencies. Consequently, they must also have differenta. amplitudesb. speedsc. wavelengthsd. all of the above
Q: If a source of sound is traveling toward you, the speed of the sound waves reaching you is _______________ the speed the sound waves would have had if the source were stationary. a. faster than b. slower than c. the same as
Q: You drop a rock in a pond, and the water waves travel away from the rock with a certain speed. You drop a heavier rock in the water. The speed of the waves in the water from the heavier rock a. remains unchanged b. increases c. decreases d. cannot be determined
Q: When the frequency of the source of a water wave increases, the speed of the waves traveling in the water a. remains unchanged b. increases c. decreases d. cannot be determined
Q: When the frequency of the source of a water wave increases, the distance between successive peaks in the wave a. remains unchanged b. increases c. decreases d. cannot be determined
Q: The wavelength of a wave multiplied by the frequency of the wave is the wave's a. speed b. frequency c. wavelength d. amplitude e. loudness
Q: The distance between peaks on a wave divided by the time for the wave to travel this distance is the wave's a. speed b. frequency c. wavelength d. amplitude e. loudness
Q: The maximum displacement of points on a wave from the equilibrium position is the wave's a. speed b. frequency c. wavelength d. amplitude e. loudness
Q: What is the symbol traditionally used to represent wavelength?a. wl b. y c. md. l
Q: The distance between two successive "˜like" points on a wave is the wave's a. speed b. frequency c. wavelength d. amplitude e. loudness
Q: The number of cycles of a wave passing a point per unit time is the wave's a. speed b. frequency c. wavelength d. amplitude e. loudness
Q: What is meant by a wave medium? a. a wave of moderate amplitude b. water c. air d. any material through which a wave travels
Q: Sound waves propagate in two dimensions.
Q: For waves moving through the atmosphere at a constant velocity, higher frequency waves must have proportionally longer wavelengths.
Q: In the troposphere segment of the Earth's atmosphere, as you increase in altitude the temperature decreases. This means the speed of sound decreases as you increase in altitude.
Q: If you increase the linear mass density of a rope, the speed of a wave on the rope also increases.
Q: Telephones don"t transmit frequencies above 3,400 Hz. Musical notes should sound normal over the telephone as long as they are below 3,400 Hz.
Q: Your vocal cords are used to produce all the sounds you make while speaking.
Q: Two identical sound producers will sound twice as loud as just one.
Q: A sound with ten times the amplitude of another sound is judged to be ten times as loud.
Q: Combining two sounds of equal intensity will give a sound level 3 dB higher than the sound level due to just one of them.
Q: A zero decibel sound level has zero amplitude.
Q: A sound level of 80 dB has twenty times the amplitude of a 60 dB sound.
Q: Two uses of ultrasound are navigation by bats and controlling insects.
Q: In ultrasound the wavelength of the sound is much smaller than in normal sound.
Q: Reverberation time of a room can be increased by covering the walls with better reflectors of sound.
Q: Reverberation can both inhibit conversation and enhance music.
Q: As you move farther away from a source emitting a pure tone, the frequency of the sound you hear decreases.
Q: In order for two waves to interfere completely destructively, they must have the same amplitude.
Q: Two speakers in a stereo emit identical pure tones. As you move around in front of the speakers, you hear the sound alternating between loud and zero. This occurs because of diffraction.
Q: When two identical waves arrive at the same place in phase, there is destructive interference.
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