Question

9) Consider a 4.00 C charge. What is the magnitude of the electric field it creates 2.56 m directly up from it?

10) Which direction is this electric field pointed? Select one: Right, Down, Left, Up

11) Consider a -4.00 C charge. What is the magnitude of the electric field it creates 2.56 m directly down from it?

12) Which direction is this electric field pointed? Select one: Up, Left, Right, Down

13) An electric field of intensity 3.50*10³ N/C is applied along the x-axis. Calculate the electric flux through a rectangular plan 0.489 m and 0.700 m long if the plane is parallel to the yz-plane (x-axis is perpendicular to it).

14) A charged particle A exerts a force of 4.68 N to the right on an electron (q=-e=-1.6*10^-19 C) which is 13.7 mm from it. What is the magnitude of the charge of particle A?

Answer 1

Electric field due to a charged particle having charge ' q ' at a distance ' r ' is given by

  

Where,   

And the direction of the field is always towards the particle for negatively charged particle and away from the particle for positively charged particle.

The force on a charge particle having charge 'Q' in an electric field (E) is given by

  

(9) The magnitude of electric field for the given situation will be

(10) And the electric field will point in upward direction (away from the charge).

(11) The magnitude of electric field for the given situation will be

(12) As the given charge is negative, the electric field will point toward the the charge. Hence the electric field will point in upward direction.

(13) Electric flux through a surface is given by

Where, E is electric field and A is the area of the given surface

The area vector always points perpendicularly outward from the surface.

According to the question, E = 3.50 x 10³ N/C and, A = 0.489 x 0.700 = 0.3423 m²

Here, the direction of both field and the area vector is in the same direction (along the positive x - axis), so .

Therefore,   

  

(14) Given,  

  

and

We have,

  

or,   

Now, we have   

  

or,

or,

As the electric field is toward the charge , so the charge at A is -6.1 x 10⁵ C .

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