Answers to Physics Concept Questions (Test #4)

This page provides answers to Physics Concept Questions – Test #4.
The test contained 30 multiple choice questions.
The correct answers are bolded below.

Compressions and rarefactions are not present with
1. longitudinal waves
2. transverse waves
3. both of these
4. neither of these
5. not enough information provided
6. none of the above
7. all of the above
All other things being equal, the speed of a sound wave ____ if its wavelength increases.
1. increases
2. decreases
3. both of these
4. neither of these
5. not enough information provided
6. none of the above
7. all of the above
A 680-hertz wave with a wavelength of 1/2 meter travels in air with a speed of
1. 680 m/s
2. 6800 m/s
3. 340 m/s
4. 3400 m/s
5. 1/2 m/s
6. 1 m/s
You hear a lot of static from your radio. Is the static you hear more likely to result from receiving FM or AM radio waves?
1. FM
2. AM
3. Neither produces any static.
4. Both produce equal amounts of static.
5. not enough information provided
6. none of the above
7. all of the above
You see lightning flash in the distance, and hear the thunder 10 seconds later. Assuming that sound travels at 340 m/s through the air, how far away was the lightning strike?
1. 34 meters
2. 3.4 meters
3. 340 meters
4. 3.4 km
5. 34 km
6. 340 km
Two charges are separated by a distance of 1 meter, and experience a mutual repulsive force of 1 Newton. If the distance between the charges is changed to 2 meters, what is the resulting repulsive force?
1. 1 N
2. 2 N
3. 4 N
4. 8 N
5. 1/2 N
6. 1/4 N
7. 1/8 N
What does a lightning rod do?
1. Attracts lightning to your building
2. Repels lightning from your building
3. Collects electrons from your building
4. Collects protons from your building
5. Reduces charge buildup on your building
6. not enough information provided
7. none of the above
8. all of the above
Two charged particles are held at a certain distance from each other. When they are released, they move and the force on each particle decreases. The particles MUST both be
1. positive
2. negative
3. of the same sign
4. of opposite sign
5. not enough information provided
6. none of the above
7. all of the above
If the electrical potential of a single electron is 1-volt in an electrical field, what is the electrical potential of 10 electrons at the same spot in the field?
1. 10 volts
2. 100 volts
3. 1000 volts
4. 1 volt
5. 1/10 volts
6. 1/100 volts
A pith ball is suspended by a non-conducting fiber. When a positively charged rod is brought near the ball, but without touching it, the ball
1. becomes positively charged
2. becomes negatively charged
3. becomes lighter
4. becomes heavier
5. becomes depolarized
6. becomes polarized
What is the source of the electrons that heat up your clothes iron
1. a hydroelectric dam
2. a coal power plant
3. the power outlet in your home
4. a nuclear power plant
5. radioactivity in your clothes-iron
6. the moon shining on your clothes-iron
7. atoms in the filament of your clothes-iron
You buy a hair-dryer in another country and it is rated at 220 V. If you plug it into a 110 V outlet, the current in the dryer is ___ compared to if you plug it into a 220 V outlet.
1. the same
2. two times greater
3. four times greater
4. 110 times greater
5. half
6. a quarter
Three light-bulbs are connected in parallel across a battery. One has a thick filament, one a thin filament, and one a medium filament. Which one has the lowest voltage across the lamp.
1. Medium filament
2. thin filament
3. thick filament
4. there is no voltage across the filaments
5. voltage is the same across all three filaments
A light bulb is connected to a 200 V power source. A current of 2.0 Amps flows across the bulb. How much power is being dissipated by the bulb?
1. 200 W
2. 400 W
3. 100 W
4. 50 W
5. 800 W
6. none of the above
A voltage of 30 V is applied across a 30 ohm resistor. What is the current flowing through the resistor.
1. 0 Amps
2. 1 Amp
3. 2 Amps
4. 900 Amps
5. 300 Amps
6. 30 Amps
A magnetic field runs from the top of this page down to the bottom of this page. An electron is fired from left to right across the page. The electron is ___ by the magnetic field.
1. Indifferent to
2. attracted by
3. repelled by
4. attracted then repelled by
5. deflected out of the plane of the page
6. made to move in square patterns
A small piece of metal is attracted to a large magnet. The magnet is attracted to the small piece of metal with a force that is ____ compared to the force with which the metal is attracted to the magnet.
1. zero
2. infinite
3. very large
4. very small
5. the same
6. similar but not the same
A proton is travelling almost but not quite parallel to a magnetic field. An electron is travelling perpendicular to the same magnetic field. The force on the electron is ____ compared to the force on the proton.
1. zero
2. infinite
3. large
4. small
5. the same
6. similar but not the same
Magnetism is caused by
1. magnetons
2. magneticians
3. pieces of iron
4. pieces of gold
5. pieces of copper
6. moving magnetic charges
7. moving electric charges
Some of the planets in our Solar system have magnetic fields. The likely cause of these magnetic fields is
1. a reflection of the Sun's magnetic field
2. magnetons
3. magneticians
4. moving magnetic charges in the core of the planets
5. moving magnetic charges in the atmosphere of the planets
6. moving electric charges in the core of the planets
7. pieces of iron on the planets
8. pieces of gold on the planets
9. pieces of copper on the planets
Blue light has ___ wavelength compared to Red light.
1. the same
2. longer
3. zero
4. infinite
5. shorter
6. none of the above
Earth's atmosphere lets in most
1. infrared light
2. ultraviolet light
3. visible light
4. of any kind of radiation
5. none of the above
6. all of the above
Which of these waves have the longest wavelength?
1. infrared light
2. ultraviolet light
3. red light
4. blue light
5. X-rays
6. yellow light
7. radio waves
An electromagnetic wave has a wavelength of 1 m. What is its frequency?
1. 1 Hertz
2. 3 Hz
3. 300 Hz
4. 3000 Hz
5. 30,000 Hz
6. 300,000 Hz
7. 3,000,000 Hz
8. 300,000,000 Hz
If Proxima Centauri, our closest star, were to explode right now, it would take about 4 years for us to know about it because
1. it takes 4 years to build a big telescope to see the star
2. it takes 4 years to obtain funding to build the necessary telescope
3. the star is 4 years old
4. it takes 4 years for the light from this star to reach us
5. it takes 4 years for a signal from us to reach the star
6. it takes 4 years for us to travel by space-ship to the star
The colors on your computer monitor arise by color
1. mixing
2. multiplication
3. addition
4. division
5. subtraction
6. exponentiation
Sunsets can appear reddish due to
1. reflection from red smog in the air
2. reflection from blue smog in the air
3. reflection from red dust particles in the air
4. reflection from blue dust particles in the air
5. blue light being scattered away by small particles in the air
6. red light being scattered away by large particles
Clothes of a certain color can appear black in a room that is lit by a light that is
1. the same color as the clothes
2. the complementary color of the clothes
3. red in color
4. blue in color
5. white in color
6. the supplementary color of the clothes
Which will take longer to warm up in the summer sunlight
1. a white house
2. a black house
3. a brown house
4. a pink house
The sky is the clearest and deepest blue when there are ____ dust particles in the air
1. many
2. very few
3. very many
4. infinite numbers of
5. large sized
6. medium sized

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