Question

Pls help me to answer this​

Answer 1

Answers:

1. True
2. True
3. True
4. True
5. True
6. True
7. True
8. False
9. True
10. True

Weirdly it seems like each answer choice, except problem 8, is "true".

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Explanations:

1. Think of a pebble dropping into a water to cause a ripple. The energy going outward in all directions requires the water as the medium for that energy wave to travel. Each particle bumps into another to transfer the energy.
2. This is fairly self explanatory that I'm not sure what to write as an explanation here.
3. Longitudinal waves are ones where they act like a slinky. A blast of energy causes compression and that compression leads to expansion later on (followed by further cycles of compression+expansion). This chain reaction causes a domino effect so the sound wave reaches the target to be absorbed or reflected.
4. This is true because light is much faster than sound. This is why fiberoptic cables are used to transmit voices on a telephone line rather than use the sound of the voices themselves to transmit. It's also why, during a thunderstorm, a flash of light strikes first before the rumbling sound of thunder follows a few seconds after.
5. This is true and it shouldn't take too much convincing to see how "electromagnetic" breaks up into "electrical" and "magnetic". These types of waves can travel through the empty vacuum of space without needing a medium like mechanical waves do. This is why energy of the sun can reach us. Visible light is part of the spectrum along with stuff like x-rays, gamma rays, microwaves, and radio waves.
6. There's not much to say here. Shadows are the absence of light.
7. This is true because a beam of light bounces off an object, and reflects into our eyes so we can see the object.
8. Unlike every other answer choice, this answer is false. Doctors don't use microwaves to get pictures of teeth and bones. Instead they use x-rays.
9. This is true. Refer to the ROYGBIV color scale for more info.
10. This seems a bit vague. Does your teacher mean visible light? If so, then yes our eyes can detect it. Otherwise for things like x-rays we cannot detect these wavelengths. I'll assume visible light for now.