Physical Science (Grade 8) Midterm — Units 5–6

Part 1: Multiple Choice

1. Using KE = ½mv², what is the kinetic energy of a 2 kg ball moving at 3 m/s?
   1. A. 6 J
   2. B. 9 J
   3. C. 18 J
   4. D. 3 J
2. What does the law of conservation of energy state?
   1. A. Energy is used up when work is done
   2. B. Energy is created by machines
   3. C. Energy disappears as heat
   4. D. Energy cannot be created or destroyed, only changed in form
3. Which is a renewable energy resource?
   1. A. Natural gas
   2. B. Oil
   3. C. Wind
   4. D. Coal
4. A book resting on a high shelf has which type of stored energy?
   1. A. Gravitational potential energy
   2. B. Thermal energy
   3. C. Kinetic energy
   4. D. Sound energy
5. A metal spoon in hot soup gets hot along its handle. What type of heat transfer is this?
   1. A. Radiation
   2. B. Conduction
   3. C. Convection
   4. D. Insulation
6. Using GPE = mgh with g = 9.8 m/s², what is the potential energy of a 5 kg object 10 m above the ground?
   1. A. 50 J
   2. B. 98 J
   3. C. 490 J
   4. D. 4,900 J
7. The energy of a moving object is called what?
   1. A. Chemical energy
   2. B. Kinetic energy
   3. C. Nuclear energy
   4. D. Potential energy
8. At which point does a roller coaster car have the most gravitational potential energy?
   1. A. Halfway down the first hill
   2. B. At the lowest point of the track
   3. C. While moving fastest at the bottom
   4. D. At the top of the highest hill
9. What energy change happens in a solar panel?
   1. A. Chemical energy to light energy
   2. B. Thermal energy to chemical energy
   3. C. Electrical energy to light energy
   4. D. Light energy to electrical energy
10. How does energy from the Sun reach Earth through space?
    1. A. Convection
    2. B. Conduction
    3. C. Friction
    4. D. Radiation
11. In a simple series circuit with three bulbs, what happens if one bulb burns out?
    1. A. The other bulbs flicker on and off
    2. B. Only that bulb goes out
    3. C. All the bulbs go out
    4. D. The other bulbs get brighter
12. What happens when the north poles of two magnets are brought together?
    1. A. They repel each other
    2. B. They lose their magnetism
    3. C. They attract each other
    4. D. They become electrically charged
13. A generator converts which form of energy into electrical energy?
    1. A. Nuclear energy
    2. B. Mechanical energy
    3. C. Light energy
    4. D. Chemical energy
14. Which material is the best conductor of electricity?
    1. A. Plastic
    2. B. Copper
    3. C. Glass
    4. D. Rubber
15. Why can't sound travel through the near-vacuum of outer space?
    1. A. Sound only travels during the day
    2. B. Starlight blocks sound waves
    3. C. Sound needs matter to travel through
    4. D. Space is too cold for sound
16. Which type of electromagnetic wave carries the most energy?
    1. A. Microwaves
    2. B. Gamma rays
    3. C. Visible light
    4. D. Radio waves
17. How can you make an electromagnet stronger?
    1. A. Use fewer coils of wire
    2. B. Add more coils of wire
    3. C. Remove the iron core
    4. D. Reduce the electric current
18. A wave has a frequency of 5 Hz and a wavelength of 2 m. What is its speed?
    1. A. 2.5 m/s
    2. B. 7 m/s
    3. C. 0.4 m/s
    4. D. 10 m/s
19. What is the highest point of a transverse wave called?
    1. A. Crest
    2. B. Trough
    3. C. Frequency
    4. D. Wavelength
20. Using V = I × R, what current flows through a 4 Ω resistor connected to 12 V?
    1. A. 3 A
    2. B. 8 A
    3. C. 16 A
    4. D. 48 A

Part 2: Written Response

21. Compare a series circuit and a parallel circuit. Explain which type is used in homes and why.