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PHYSICS FINAL EXAM REVIEW. Answer Key! Text me if you have any questions! (Especially 1 st 3 rd and 6 th period ). 1. B. Frequency is the number of waves/vibrations/pulses/oscillations that occur in one second. Frequency is measured in Hertz.
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PHYSICS FINAL EXAM REVIEW Answer Key! Text me if you have any questions! (Especially 1st 3rd and 6th period )
1. B Frequency is the number of waves/vibrations/pulses/oscillations that occur in one second. Frequency is measured in Hertz. Period is the number of seconds per wave, or 1/f Amplitude Wavelength
2. B, 12. A • Refraction is when the light bends as it changes the medium it’s traveling through (air to glass, glass to water, water to air, etc)
3. A, 11. C • Refraction and Diffraction are BOTH about waves bending, but for different reasons. Diffraction is when they spread out around the edge of a wall, or as they go through a hole in a wall:
4. D • Remember, in physics, “reflection” doesn’t mean what you see in the mirror (that’s an image). Reflection is when waves bounce off of an object. An echo happens when sound waves reflect off of a barrier and come back to your ear.
5. B Sound waves are the most common example of a longitudinal wave. Longitudinal waves happen when the particles of the medium move back in forth in the same direction as the wave is moving:
6. B, 7. C • As it passes you, the apparent frequency suddenly drops, resulting in a low pitch: • http://www.physicsclassroom.com/Class/sound/u11l3b.cfm
8. D • High frequency = high pitch • Low frequency = low pitch • http://plasticity.szynalski.com/tone-generator.htm <-- This website lets you pick a frequency and will play the sound so hear the difference between a high frequency and a low frequency (only works in firefox) • (The LOUDNESS depends on the amplitude.)
9. A • Electromagnetic waves do not require a medium to travel through. They are transverse waves.
10. B • Transparent = lets all light through (window) • Opaque = lets no light through (wall) • Translucent = lets some light through (frosted window) • Luminous = gives off light (light bulb)
14. A • Remember the electric field hockey simulation: http://phet.colorado.edu/en/simulation/electric-hockey • To change the force on the “puck” you can change the charge of the puck OR change the size of the field.
15. A • Ohm’s Law says I = V/R • I = Current (measured in amps) - Current is the amount of charge flowing • V= Voltage (measured in volts)- Voltage is the energy per charge • R = Resistance (measured in ohms Ω)- Resistance resists or slows down the flow of charge. • According to the equation, if V increases, then so does I. If R decreases, I increases.
16. D • Ammeters measure amps (units of current) • Voltmeters measure volts (units of voltage) • Ohmmeters measure ohms (units of resistance)
17. C • One path only:
18.A RT = R+R+R+R = 4R
19. D • Three paths:
20. B • A circuit breaker uses an electromagnet to literally “break the circuit” if there is a dangerous level of current. (This was one of our uses of electromagnets – remember the Brainpop video we watched on electromagnets – or rewatch it. Text me for the password) • A fuse does the same thing with a melting wire and has to replaced each time, while a circuit breaker can be reset.
21. B • Moving charges create a magnetic field – an electromagnet. • We can increase the strength by: • -Increasing the current (usually by increasing the voltage) • - Wrapping the wire into coils – more coils = stronger magnetic field • - wrapping the wire around an iron core (or any other ferromagnetic material – ferromagnetic = attracted to magnets)
27. TRUE • F = ILB
