D. chemical to electrical to sound and electromagnetic
Answer:
The smallest possible beat frequency when B and C are sounded together is 3 Hz
Explanation:
Given;
the beat frequency of A and B = 2 Hz
the beat frequency of A and C = 5 Hz
Beat frequency is equal to the difference in frequency of the two notes that interfere to produce the beats.

Therefore, the smallest possible beat frequency when B and C are sounded together is 3 Hz
D. Acts at a distance, because magnetic forcefield is in two dots, Earth's north and south magnetic poles, and magnet is on some distance from them.
Answer:
Its angular speed is 0.105 rad /s. The minute hand of a clock takes 60 minutes = 60 x 60 seconds to complete one rotation.
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Explanation:
Out of all the options, only body massager which uses electric energy to move back and forth is using motor here. It is because a motor converts electrical energy to Mechanical energy and only massager obeys it among all the options.
In short, Your Answer would be Option C
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