Most likely to be b.entering the formal operational stage
Answer:
The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field.
Explanation:
Answer:

Explanation:
Given:
electric field, 
charge, 
initial position coordinates, 
final position coordinates, 
We find the distance through which the charge has been moved:

Where we have (x1,y1) & (x2,y2) as the initial and final coordinates of the points.


Now we need the angle through which displacement is made with respect to the direction of electric field.

![\theta= tan^{-1}[\frac{76-(-131)}{107-(-81)} ]](https://tex.z-dn.net/?f=%5Ctheta%3D%20tan%5E%7B-1%7D%5B%5Cfrac%7B76-%28-131%29%7D%7B107-%28-81%29%7D%20%5D)

Now from the relation between the change in potential difference:



∵The change in voltage is defined as the work done per unit charge.
∴

Putting the respective values


I think it’s c) a transverse wave is made of particles that move perpendicular to the motion of the wave