I need to check my answers!!

Which of these is not in the family
a. sound
b. light
c. infrared radiation (answer)
d. radio waves

When an electric charge is shaken to and fro in quick succession, the vibrating charge emits
a. infrasonic sound
b. Ultrasonic sound
c. an electromagnetic wave (answer)
d. gamma radiation

If you dip your finger repeatedly onto the surface of still water, you produce waves. The more frequently you dip your finger, the
a. lower the wave frequency and the longer the wavelength
b. higher the wave frequency and the shorter the wavelength (answer)
c. both of the above
d. neither

Low-pitched sounds have
a. low frequencies
b. long periods
c. both (answer)
d. none

I was so confused by this question!! Any advice??

Suppose at a concert a singer’s voice is a radio broadcast all the wave around the world before reaching the radio you hold to your ear. This takes 1/8 seconds. If you’re close, you her her voice in the air before you hear it from the radio. But, if you are far away, both singnals will reach you at the same time. How many meters distant must you be for this to occur!!

Would it be 1 meter or 8 meters?? I think it’s 8!

To check your answers, let's go through each question one by one:

1. Which of these is not in the family
a. sound
b. light
c. infrared radiation (answer)
d. radio waves

To find the correct answer, we need to identify which option does not belong to the same family as the others. In this case, sound, light, and radio waves all belong to the electromagnetic spectrum, while infrared radiation is also a form of electromagnetic radiation but at a different wavelength than visible light. Therefore, the answer is (c) infrared radiation.

2. When an electric charge is shaken to and fro in quick succession, the vibrating charge emits
a. infrasonic sound
b. ultrasonic sound
c. an electromagnetic wave (answer)
d. gamma radiation

In this question, we are looking for the type of emission produced when an electric charge is shaken. To determine the answer, we need to understand that sound waves are produced by vibrating objects, while electromagnetic waves are produced by oscillating charges. Therefore, the correct answer is (c) an electromagnetic wave.

3. If you dip your finger repeatedly onto the surface of still water, you produce waves. The more frequently you dip your finger, the
a. lower the wave frequency and the longer the wavelength
b. higher the wave frequency and the shorter the wavelength (answer)
c. both of the above
d. neither

To determine the relationship between the frequency and wavelength of the waves produced, we need to understand the properties of waves. The frequency of a wave refers to how many waves pass a point per second, while the wavelength represents the distance between two consecutive wave peaks. By dipping your finger more frequently, you would be increasing the number of waves passing a point per second, resulting in a higher frequency. As a result, the distance between wave peaks (wavelength) would be shorter. Therefore, the correct answer is (b) higher the wave frequency and the shorter the wavelength.

4. Low-pitched sounds have
a. low frequencies
b. long periods
c. both (answer)
d. none

To determine the properties of low-pitched sounds, we need to understand the relationship between pitch and frequency. Pitch is the subjective perception of how high or low a sound is, and it correlates with the frequency of the sound wave. Low-pitched sounds have lower frequencies, so the correct answer is (a) low frequencies.

As for the last question about the singer's voice reaching you in the air before reaching the radio, the information provided is not sufficient to determine the exact distance. However, it does indicate that you hear the voice in the air before the radio signal. Therefore, it implies that you are closer to the source of the singer's voice than to the radio. So, it is more likely that the answer is closer to 1 meter rather than 8 meters. However, without more specific information, it is difficult to give a definitive answer.

Overall, I hope this explanation helps in checking your answers and understanding the concepts behind them!