Download Grade 7 Physical Posttest

Grade 7 Physical Posttest
Select the best answer to each question.
____
1. Energy from the sun arrives as electromagnetic radiation with a wide range of wavelengths and frequencies.
Which form of electromagnetic radiation has more energy than visible light waves have?
A.
B.
C.
D.
____
microwaves
radio waves
infrared waves
ultraviolet waves
2. These graphs show two different types of electromagnetic radiation.
ELECTROMAGNETIC RADIATION
If Graph I shows ultraviolet radiation, what type of electromagnetic radiation would Graph II show?
A. infrared light
B. microwaves
C. violet light
D. X-rays
____
3. Felipe was enjoying the sunny day at the beach. He told his friend Carl that he was really enjoying the warm
feeling that he was getting as he sat in the Sun. Carl explained that the electromagnetic radiation was
responsible for this warm feeling. Which part of the electromagnetic spectrum was responsible for making
Felipe feel warm?
A. gamma rays
B. microwaves
C. visible light
D. infrared waves
____
4. The diagram below shows four thin beams of light interacting with a material.
Which beam best shows absorption?
A. 1
B. 2
C. 3
D. 4
____
5. Emma sets up an experiment to study light passing through different materials. What does Emma observe
happen to light at the point when it passes into a material where the speed of light changes?
A. The light is brighter.
B. The light is reflected.
C. The light is refracted.
D. The light is absorbed.
____
6. Alejandro walked into the classroom before anyone else, including the teacher, had arrived. Because it was
too dark to see anything, he turned on the lights. He was then able to see his desk. Why was Alejandro able to
see the desk?
A. The desk reflected the light.
B. The desk became a light source.
C. The desk absorbed the light when he turned it on.
D. The desk separated the light into all the wavelengths of visible light.
____
7. In 1947, pilot Chuck Yeager became the first person in an airplane to fly faster than the speed of sound. He
flew his plane about 12,000 meters above sea level. At that altitude, the speed of sound travels at 290
meters/second. At sea level, the speed of sound is about 340 meters/second. What conclusion can you make
from this information?
A. The speed of sound does not depend on altitude.
B. The speed of sound depends on the type of plane flown.
C. As the altitude increases, the speed of sound increases.
D. As the altitude increases, the speed of sound decreases.
____
8. The graph below shows the speed of waves in air and water.
What can you conclude from this graph?
A. Waves travel fastest through water.
B. Waves travel faster through water than they do through air.
C. Waves always travel at the same speed through all substances.
D. Waves cannot travel faster than 10,000 (104) meters/second (m/s).
____
9. The speed of a sound wave through a substance depends on the vibrations caused by collisions of the particles
that make up that substance. The more collisions there are, the faster the sound wave travels. The particles in
a liquid are more closely packed together than the particles in a gas. What would you predict to happen to a
sound wave as it travels from a liquid into a gas?
A. The speed of the sound wave would increase.
B. The speed of the sound wave would decrease.
C. The amplitude of the sound wave would increase.
D. The amplitude of the sound wave would decrease.
____ 10. Ashley warms a pure, solid substance. She graphs the changes in temperature as shown in the figure below.
Which process takes place during segment D?
A.
B.
C.
D.
melting
evaporation
increase in temperature of a gas
increase in temperature of a liquid
____ 11. When Roberto heats margarine in a hot skillet, what modification causes a change of state?
A.
B.
C.
D.
The margarine loses thermal energy.
The margarine loses chemical energy.
The margarine gains thermal energy.
The margarine gains chemical energy.
____ 12. Allison visits the beach. She notices that the ice cubes in her water bottle melt over the course of the day.
Which of the following best describes what occurs when ice cubes melt?
A.
B.
C.
D.
The cold ice cubes absorb heat energy from the air, and eventually the ice cubes melt.
The cold ice cubes absorb heat energy from the air, and eventually the air freezes.
The cold ice cubes release heat energy into the air, and eventually the ice cubes melt.
The cold ice cubes release heat energy into the air, and eventually the air freezes.
____ 13. Gordon throws a baseball into the air. It rises, stops momentarily when it reaches its greatest height, and then
falls back to the ground. At what point does kinetic energy convert to potential energy?
A.
B.
C.
D.
when the baseball is rising
when the baseball is falling
just after the baseball hits the ground
while the baseball is at its highest point
____ 14. During a hot summer night, Randi turns on a fan. When the fan operates, the blades rotate.
Which transformation of energy occurs to make the blades rotate?
A. chemical energy to kinetic energy
B. electrical energy to kinetic energy
C. thermal energy to potential energy
D. potential energy to electrical energy
____ 15. During a camping trip, Brittany collects wood for a campfire. Which energy conversion occurs as the wood
burns?
A.
B.
C.
D.
light energy to chemical energy
electrical energy to light energy
elastic energy to thermal energy
chemical energy to thermal energy
____ 16. A lamp releases only light and thermal energy. The energy input of the lamp is 120 watts. Of that input, 80
watts is converted to light. How much energy is converted to thermal energy?
A.
B.
C.
D.
exactly 40 watts
exactly 80 watts
less than 40 watts
more than 40 watts
____ 17. Tamara rides a roller coaster car downward from its highest point. What happens to the potential energy of the
roller coaster car as it moves?
A.
B.
C.
D.
It is destroyed and lost.
It remains at the same level.
It is converted to kinetic energy.
It increases as height decreases.
____ 18. John replaces the batteries in a flashlight as he prepares for a camping trip. Which is the best prediction of the
percentage of the chemical energy in a battery that will be available for conversion to light energy in a
flashlight?
A.
B.
C.
D.
10%
90%
100%
110%
____ 19. Emma scoops her mashed potatoes with a metal spoon.
Which statement best explains why energy as heat will flow from the mashed potatoes to the spoon?
A. The spoon is colder than the mashed potatoes.
B. The mashed potatoes are warmer than the bowl.
C. The mashed potatoes and the spoon are both solids.
D. The spoon is about the same temperature as the air.
____ 20. Myra places two objects in contact. One object is warmer than the other object. Which type of heat transfer is
she most likely testing?
A.
B.
C.
D.
conduction
convection
insulation
radiation
____ 21. Tran places a warm plate with a temperature of 60 ºC on a bench that is at a temperature of 25 ºC. After an
hour, the plate and the bench are at the same temperature. Which of the following best describes what occurs
during the hour?
A. The temperature of the plate stays the same, while the temperature of the bench increases
to 60 ºC.
B. The temperature of the bench stays the same, while the temperature of the plate decreases
to 25 ºC.
C. The temperature of the plate and the bench both decrease until they reach a temperature of
0 ºC.
D. The temperature of the plate decreases to 30 ºC, while the temperature of the bench
increases to 30 ºC.
Grade 7 Physical Posttest
Answer Section
MULTIPLE CHOICE
1. ANS: D
• A is incorrect because ultraviolet waves, not microwaves, have more energy (higher frequency, shorter
wavelength) than visible light waves.
• B is incorrect because ultraviolet waves, not radio waves, have more energy (higher frequency, shorter
wavelength) than visible light waves.
• C is incorrect because ultraviolet waves, not infrared waves, have more energy (higher frequency, shorter
wavelength) than visible light waves.
• D is correct because ultraviolet waves have more energy (higher frequency, shorter wavelength) than visible
light waves.
STA: SC.7.P.10.1
2. ANS: D
A is incorrect because the wavelengths of infrared light are longer than those of ultraviolet light.
B is incorrect because microwaves have a longer wavelength than ultraviolet radiation.
C is incorrect because ultraviolet light has shorter wavelength than violet light.
D is correct because X-rays have shorter wavelengths than ultraviolet light.
STA: SC.7.P.10.1
3. ANS: D
A is incorrect because gamma rays can penetrate most objects very easily and are not absorbed by the skin.
B is incorrect because the skin does not absorb microwaves.
C is incorrect because the skin reflects visible light.
D is correct because the skin can absorb infrared waves, which makes the skin feel warmer.
STA: SC.7.P.10.1
4. ANS: B
• A is incorrect because beam 1 is transmitted, not absorbed, by the material.
• B is correct because beam 2 is absorbed by the material. It stops in the material and is not transmitted,
scattered, or reflected.
• C is incorrect because beam 3 is scattered, not absorbed, by the material.
• D is incorrect because beam 4 is reflected, not absorbed, by the material.
STA: SC.7.P.10.2
5. ANS: C
A is incorrect because the light does not change intensity.
B is incorrect because the light will not bounce off the second material.
C is correct because the light will bend away from the boundary where the two materials meet.
D is incorrect because the light can travel through the material.
STA: SC.7.P.10.2
6. ANS: A
A is correct because the desk was illuminated so that it reflected the light when he turned it on.
B is incorrect because the desk does not produce light.
C is incorrect because the desk would not be seen if it absorbed the light that struck it.
D is incorrect because the desk does not allow light to pass through it.
STA: SC.7.P.10.2
7. ANS: D
A is incorrect because the passage states that sound waves travel at different speeds, depending on altitude.
B is incorrect because the speed at which sound travels depends on the medium through which it travels.
C is incorrect because the passage states that sound travels faster at sea level.
D is correct because the passage states that the speed of sound at sea level is faster than at 12,000 meters
above sea level.
STA: SC.7.P.10.3
8. ANS: B
A is incorrect because the graph does not show how waves travel through other materials.
B is correct because waves travel over 1000 m/s in water and less than this speed in air.
C is incorrect because the graph shows differences in wave speeds.
D is incorrect because this graph shows waves traveling only through gases and a liquid, and not through
solids. Waves travel fastest through solids.
STA: SC.7.P.10.3
9. ANS: B
A is incorrect because fewer particles in a given volume of gas will result in fewer collisions and therefore a
slower speed.
B is correct because there will be fewer collisions between particles in a gas, resulting in a decreased speed.
C is incorrect because the speed and not the amplitude of the sound wave is affected.
D is incorrect because the speed will change as the sound wave moves into a different medium.
STA: SC.7.P.10.3
10. ANS: B
• A is incorrect because melting takes place during segment B.
• B is correct because the substance is a liquid during segment C. As thermal energy is added, the substance
changes to a gas at segment D.
• C is incorrect because temperature does not change as energy is added at segment D.
• D is incorrect because temperature does not change as energy is added at segment D.
STA: SC.7.P.11.1
11. ANS: C
A is incorrect because the margarine gains thermal energy.
B is incorrect because the change of state occurs due to a change in thermal energy.
C is correct because the margarine gains thermal energy, which causes a change of state from solid to liquid.
D is incorrect because the margarine gains thermal energy, not chemical energy.
STA: SC.7.P.11.1
12. ANS: A
A is correct because heat energy flows from the warmer air to the colder ice cubes, and the temperature of the
ice cubes increases until the ice cubes reach their melting point.
B is incorrect because the ice melts; the air does not freeze.
C is incorrect because the ice cubes absorb, not release, heat energy.
D is incorrect because the ice cubes absorb heat energy and become warmer. The air does not freeze as a
result.
STA: SC.7.P.11.1
13. ANS: A
• A is correct because as the baseball is rising, its kinetic energy is being converted to potential energy.
• B is incorrect because when the baseball is falling, its potential energy is being converted to kinetic energy.
• C is incorrect because there would be no energy conversion just after the baseball hits the ground.
• D is incorrect because no energy conversion is taking place while the baseball is still at its highest point.
STA: SC.7.P.11.2
14. ANS: B
A is incorrect because an electrical outlet is a source of electrical energy, not chemical energy.
B is correct because the electric fan converts electrical energy to kinetic energy, which causes the blades to
rotate.
C is incorrect because some of the potential energy, in the form of electrical energy, would be converted to
thermal energy, but thermal energy is not converted to potential energy.
D is incorrect because the conversion is from electrical energy, which is a form of potential energy, not to
electrical energy.
STA: SC.7.P.11.2
15. ANS: D
A is incorrect because the energy conversion is from chemical energy to light energy, not light energy to
chemical energy.
B is incorrect because wood stores energy in the form of chemical energy, not electrical energy.
C is incorrect because wood stores energy in the form of chemical energy, not elastic energy.
D is correct because wood stores energy in the form of chemical energy, and chemical energy converts to
thermal energy when the wood burns.
STA: SC.7.P.11.2
16. ANS: A
• A is correct because if the input is 120 watts and energy cannot be destroyed, the output must also be 120
watts, so 40 watts must be thermal energy.
• B is incorrect. The total output cannot be greater than the total input, because energy cannot be created.
• C is incorrect. The total output cannot be less than the total input, because energy cannot be destroyed.
• D is incorrect. The total output cannot be greater than the total input, because energy cannot be created.
STA: SC.7.P.11.3
17. ANS: C
A is incorrect because energy can be converted from one form to another, but it cannot be destroyed.
B is incorrect because potential energy would decrease as the roller coaster car’s height decreased.
C is correct because gravitational potential energy is converted to kinetic energy as the roller coaster car
moves downward.
D is incorrect because potential energy decreases as height decreases.
STA: SC.7.P.11.3
18. ANS: B
A is incorrect because this is a good prediction of the amount of chemical energy lost as heat energy.
B is correct because in the conversion from chemical energy to light energy, some of the energy is converted
to heat energy. The energy that could be converted to light energy is likely to be about 90%.
C is incorrect because 100% of the chemical energy could not be converted to light energy because some
energy is always converted to heat energy.
D is incorrect because the energy converted to light energy cannot be greater than the amount of chemical
energy stored in the battery.
STA: SC.7.P.11.3
19. ANS: A
A is correct because energy as heat flows from warmer objects to cooler ones. The heat flows from the
warmer mashed potatoes to the colder spoon.
B is incorrect because this statement explains why energy as heat will flow from the mashed potatoes to the
bowl, not from the mashed potatoes to the spoon.
C is incorrect because this statement does not explain the transfer of energy as heat.
D is incorrect because this statement explains why energy as heat will not flow from the spoon to the air, but
it does not explain why energy as heat will flow from the mashed potatoes to the spoon.
STA: SC.7.P.11.4
20. ANS: A
A is correct because conduction is the transfer of heat between two objects that are in contact with each other.
B is incorrect because convection is the transfer of heat caused by the movement of particles in a liquid or a
gas.
C is incorrect because insulation is a property of a material that makes it resistant to heat transfer.
D is incorrect because radiation is the transfer of heat by electromagnetic waves and occurs without objects
being in contact with each other.
STA: SC.7.P.11.4
21. ANS: D
A is incorrect because heat energy will be transferred from the warm plate to the cooler bench, so the
temperature of the plate would decrease.
B is incorrect because heat energy will be transferred from the warm plate to the cooler bench, so the
temperature of the bench would increase.
C is incorrect because the temperature of the plate will decrease until it reaches the same temperature as the
plate.
D is correct because heat energy will be transferred from the warm plate to the cooler bench. The plate will
become cooler, while the bench will become warmer.
STA: SC.7.P.11.4