The medium is the component of communication through which information is transferred. The correct option in the given question is option "c". Medium is actually the means through which communication is done. It can be a an oral message or written message or it can be nonverbal or symbolic. Any kind of message transmission requires a medium and without an medium no message can be transmitted. Whenever people talk on the telephone or write a letter, there has to be a medium for transmitting the message to the person on the other side.
Answer:
Charge on each metal sphere will be 
Explanation:
We have given number of electron added to metal sphere A 
As both the spheres are connected by rod so half -half electron will be distributed on both the spheres.
So electron on both the spheres 
We know that charge on each electron 
So charge on both the spheres will be equal to 
So charge on each metal sphere will be equal to 
Their relative speed is the sum of 60 and 40 or 100km/hr. They will travel the 150km in 1.5 hrs. When two object approach each other, the closing speed is just the sum of the speeds, therefore, the closing speed is your case is 100kph. So they will meet in 1.5 hours.