Hello I hope you are having a great day :)
Your question: When a light switch is turned on, the light comes on immediately because....
The answer is: the electrons in the wire are instantly "pushed" by a voltage difference making the the light switch on.
Hopefully that helps you :)
Knowing the direction of a force is important because it helps someone know the motion of the object. if you use a free body diagram, then it becomes easy to see all the forces being applied to an object. if there is more force going one way, the object is accelerating in that direction. if all the forces cancel each other out, then the object is at a constant speed or is at rest.
To solve the problem we will simply perform equivalence between both expressions. We will proceed to place your units and develop your internal operations in case there is any. From there we will compare and look at its consistency


At the same time we have that



Therefore there is not have same units and both are not consistent and the correct answer is B.