Question

QUESTION 1:

Are electric force and electric field vector or scalar quantities?

		electric force is a scalar electric field is a vector
		electric force is a vector electric field is a scalar
		electric force and electric field are both scalars
		electric force and electric field are both vectors

QUESTION 2:

When an electron is placed in an electric field it experiences an electrostatic force towards the North.  In what direction is the electric field?

		Towards the East
		Towards the West
		Towards the South
		Towards the North

QUESTION

What is the magnitude of the electric field at a distance of 66 cm from a 76 μC charge, in units of N/C?

Answer 1

QUESTION 1 :

Ans. :- Electric force and Electric field both are vector.

ELECTRIC FORCE :

Just like in Classical mechanics Gravitational force between any two masses and direction of force is given by Newton's law of gravitation similarly force between any two charges and its direction is given by Coulomb's law which is

Coulomb's law :

Force between any two charges is directly proportional to product of two charges and inversely proportional to the square of distance between them.

Force due to charge q on Q is given by

  

where ε is permittivity of free space.

r is distance between q and Q

This force is either repulsive or attractive depending upon charges and it points along the line from q to Q.

thus from above we can say that electric force is vector.

ELECTRIC FIELD :

Suppose there are two charges Source charge q ( which is responsible for generation of field  and )test charge Q then electric field at point P is

     

where magnitude of electric field at any point is E = F/q and direction of E is that of force F which acts on test charge Q.

THUS ELECTRIC FIELD IS ALSO VECTOR.

QUESTION 2

Ans. We know that

because of negative charge of electron charge of Electric field will be opposite to that that electric force and since force is in North Direction. Electric field will be in South.