What is the magnitude of the electric field at the dot in the figure?
(E=? V/m) What is the direction of the electric field.
- to the left
- to the right
- upward
- downward
Concepts and reason
The main concepts required to solve the given question are electric field and electric potential.
The magnitude and direction of electric field was found using the relation equating potential difference with electric field and distance.
Initially, calculate the magnitude of the electric field at the position marked in the figure and then the direction of electric field is find out by using the relationship between the electric field and electric potential.
Fundamentals
Electric Potential is a quantity numerically equal to the potential energy of a unit positive charge at a given point of the field.
Electric Field is the region around a charged object within which a force would be exerted on other charged objects.
The relation between electric field and potential difference is given by,
Answer:
(a)
The magnitude of electric field can be found by,
Here,V is the potential difference,D is the distance and E is the electric field.
Rearrange the above equation.
…1
The potential difference between the two plates in the arrangement with potential at 
(b)
The electric field is given as,
Here,V is the electric potential.
The direction of the electric field is from high potential to the low potential. Since, the direction of potential is towards right.
Hence, the options (2), (3) and (4) are incorrect.
Therefore, the electric field is directed from right to the left.