Sound wave > electric signal > radio wave > sound wave
Frictional force and Applied force has same “magnitude” and “opposite” direction.
Option: B
<u>Explanation</u>:
When a book is moved horizontally by applying “force” on the book, the frictional force is opposed to the book by the table. Here, this “frictional force” is opposing the book has the same force what we applied on the book but this frictional force and the applied force are opposite in direction. Always the “frictional force” is opposite to the “applied force” which stops the object to move. For example, if a force applied leftward to the object the frictional force is acted on the right side of the object.
When two objects are in contact they experience a "frictional force". This "frictional force" acts opposite to the force applied on to move the object.
Formula for "frictional force" is 
Where,
is coefficient of friction and N is normal force.
<h2>Question:</h2>
Appliances connected so that they form a single pathway for charges to flow are connected in a(n)
<h2>Answer:</h2>
<u>A</u><u>.</u><u> </u><u>Series</u><u> </u><u>circuit</u><u> </u>
<h2>
<u>#CARRYONLEARNING</u><u> </u></h2><h2>
<u>#STUDYWELL</u><u> </u></h2>
The correct answer is sulfur dioxide pollution
Hope this helped :)
I don't really know what it's about but everything looks okay to me. There might be some mistakes on the last sentence but i'm not completely sure.