Exam 23: Electric Fields

A particle (q = 3.0 mC,m = 20 g)has a speed of 20 m/s when it enters a region where the electric field has a constant magnitude of 80 N/C and a direction which is the same as the velocity of the particle.What is the speed of the particle 3.0 s after it enters this region?

A 24-nC charge is distributed uniformly along the x axis from x = 2 m to x = 6 m.Which of the following integrals is correct for the magnitude (in N/C)of the electric field at x = +8 m on the x axis?

If Q = 20 μC and L = 60 cm,what is the magnitude of the electrostatic force on any one of the charges shown?

A +20-nC point charge is placed on the x axis at x = 2.0 m,and a −25-nC point charge is placed on the y axis at y = −3.0 m.What is the direction of the electric field at the origin?

Rubber rods charged by rubbing with cat fur repel each other.Glass rods charged by rubbing with silk repel each other.A rubber rod and a glass rod charged respectively as above attract each other.A possible explanation is that

Three point charges,two positive and one negative,each having a magnitude of 20 μC are placed at the vertices of an equilateral triangle (30 cm on a side).What is the magnitude of the electrostatic force on the negative charge?

Identical point charges Q are placed at each of the four corners of a 3.0 m × 4.0 m rectangle.If Q = 40 μC,what is the magnitude of the electrostatic force on any one of the charges?

Charge of uniform density 4.0 nC/m is distributed along the x axis from x = −2.0 m to x = +3.0 m.What is the magnitude of the electric field at the point x = +5.0 m on the x axis?

Two charged particles,Q₁ and Q₂,are a distance r apart with Q₂ = 5Q₁.Compare the forces they exert on one another when Is the force Q₂ exerts on Q₁ and Is the force Q₁ exerts on Q₂.

Enrico says that positive charge is created when you rub a glass rod with silk,and that negative charge is simply the absence of positive charge.Rosetta says that negative charge is created and that positive charge is the absence of positive charge.(She has heard that Ben Franklin should have reversed the signs he associated with the charges. )Which one,if either,is correct?

In a diagram of charges and electric field lines charge Has twelve field lines going outward from it and charge Has three field lines going into it.If one of the charges is 100 nC,what is the other one?

The velocity of a particle (m = 10 mg,q = −4.0 μC)at t = 0 is 20 m/s in the positive x direction.If the particle moves in a uniform electric field of 20 N/C in the positive x direction,what is the particle's speed at t = 5.0 s?

If Q = 25 μC,q = 10 μC,and L = 40 cm in the figure,what is the magnitude of the electrostatic force on q?

A uniform linear charge of 2.0 nC/m is distributed along the x axis from x = 0 to x = 3 m.Which of the following integrals is correct for the y component of the electric field at y = 4 m on the y axis?

A +15-nC point charge is placed on the x axis at x = 1.5 m,and a −20-nC charge is placed on the y axis at y = −2.0m.What is the magnitude of the electric field at the origin?

A negatively charged particle is moving in the +x-direction when it enters a region with a uniform electric field pointing in the +x-direction.Which graph gives its position as a function of time correctly? (Its initial position is x = 0 at t = 0. )

A uniformly charged rod (length = 2.0 m,charge per unit length = 3.0 nC/m)is bent to form a semicircle.What is the magnitude of the electric field at the center of the circle?

Two tiny metal spheres are fixed to the ends of a non-conducting string of length )Equal charges,+q,are placed on the metal spheres.Randall says that the force on the string has magnitude )Tilden says that the tension in the string has magnitude )Which one,if either,is correct?

When a positive charge q is placed in the field created by two other charges Q₁ and Q₂,each a distance r away from q,the acceleration of q is

Two imaginary spherical surfaces of radius R and 2R respectively surround a positive point charge Q located at the center of the concentric spheres.When compared to the number of field lines N₁ going through the sphere of radius R,the number of electric field lines N₂ going through the sphere of radius 2R is