Forces and Motiontest

Final Exam Study Guide

8th Grade PSI Science Name ______

Major Concepts:

1) What is a wavelength?

2) What is frequency?

3) What is amplitude?

4) What is a medium, and why does a sound wave need one to travel?

5) What does it mean for light to be reflected?

6) What does it mean for light to be absorbed?

7) When does light travel in a straight line?

8) When does light bend while it travels?

9) What is the wave model of light?

10) Why isn’t light a matter wave?

11) Why are digital signals more reliable than other ways of transmitting information?

Multiple Choice:

1) Which of the following is true?

a) As amplitude increases, wavelength increases

b) As amplitude increases, frequency increases

c) As wavelength decreases, frequency increases

d) As frequency increases, wavelength increases

2) Which of the following is not a part of a wave?

a) Crest

b) Trough

c) Node

d) Frequency

3) What is the speed of a wave that is 4.5m long and has a frequency of 150Hz?

a) 0.03 m/s

b) 33.3 m/s

c) 154.5 m/s

d) 675 m/s

4) What happens to the speed of a wave when it enters a new medium?

a) It stays the same

b) It goes up

c) It goes down

d) It depends on what the new medium is

5) What happens to sound if it encounters a vacuum?

a) It moves faster

b) It moves slower

c) It cannot continue

d) It reflects back the way it came

6) What happens to the energy of an object if it absorbs light?

a. It goes up

b. It goes down

c. It stays the same

d. It depends on the light

7) Which color of visible light has the most energy?

a. red

b. orange

c. green

d. violet

8) When you look into a mirror and see a reflection, what happened to the light?

a. It was absorbed

b. It was reflected

c. It was refracted

d. Nothing

9) How does a magnifying glass work?

a. It bends light changing the size an object appears to be

b. It creates more light making the object bigger

c. It absorbs like making the object bigger

d. It brings the object physically closer and makes it physically larger

10) How does light act like a wave?

a. It curves around corners like sound

b. It travels in a straight line

c. It is affected by the moon like water tides

d. The molecules in light bump against each other

11) What two things are necessary for communication?

a. Two telephones

b. Two computers

c. Two people

d. A sender and a receiver

12) Which of the following is not part of the electromagnetic spectrum?

a. Visible light

b. X-rays

c. Sound waves

d. Radio waves

13) Why are electromagnetic waves preferred over sound waves to carry information?

a. They travel faster

b. They do not need a medium

c. They do not emit sound while they travel

d. All of the above

14) Which kind of communication requires wire to travel?

a. Telegraph

b. Cell phones

c. Satellite

d. Bluetooth

15) Instead of having wires, cordless phones must have which of the following to communicate?

a. Sunlight

b. X-ray signal

c. Microwave signal

d. Visible light signal

Free Response

1. Unit 5: Draw a picture of a repeating wave and label the major parts.

2. Unit 5: Explain the difference between a transverse and a longitudinal wave.

3. Unit 6: Explain the difference between light being reflected and being absorbed.

4. Unit 6: Will all objects absorb the same frequencies of light? Give an example to support your claim and explain.

5. Unit 7: What are some ways that human beings communicate by passing digital signals through wires?

6. Unit 7: What are some ways that human beings communicate by passing signals without wires?

7. Unit 7: If people on Earth want to communicate with astronauts on the international space station, why do they need to use electromagnetic waves to do so?