Electric Field WS Physics 2

Electric Field WS – Physics 2

1. At a point in space an electron feels an electric force vertically upward. What is the direction of the electric field at that point?

2. Why can electric field lines never cross?

3. An isolated electron experiences an electric force of 6.4 x 10-14 N. What is the magnitude of the electric field at -19 that location? (qe = 1.6 x 10 C)

4. What is the magnitude and direction of an electric field that would just support the weight of an electron? (m = 9.11 x 10-31 kg)

5. What is the magnitude of the electric field at a point 0.25 cm away from a point charge of +4.0 x 10-6 C?

6. Two charges, - 4.0 μC and - 5.0 μC, are separated by a distance of 20.0 cm. What is the electric field intensity halfway between the charges? ( 1 μC = 1 x 10-6 C )

7. Two charges, + 3.0 μC and +4.0 μC, are located at (-0.50m, 0) and (0.75 m, 0), respectively. Where on the x- axis is the electric field zero?

8. An electron is placed in an electric field of 2.5 x 103 N/C directed along the +y-axis. What is the force on the electron?

ANSWERS: 3. 4.0 X 105 N/C 4. 5.6 X 10-11 N/C, down 5. 5.8 x 109 N/C 6. 9.0 x 105 N/C toward -5 μC charge 7. (0.080 m , 0) 8. 4.0 x 10-16 N in the –y direction Electric Potential WS (Physics 2)

1) The electric field intensity between two charged parallel plates is 1.00 x 10-3 N/C. If the plates are 2.55 cm apart, what is the potential difference of the plates?

2) A rechargeable D-cell has a voltage of 1.25 V. The average distance between the parallel plates which make up this electrochemical cell is 0.850 cm. What is the magnitude of the electric field intensity inside?

3) During a thunderstorm, then underside of a cloud becomes positively charged, which induces a negative charge on the ground underneath it (just like two parallel plates). If the potential difference between the cloud and the ground is 1.20 gigavolts ( 1 GV = 1 x 109 V) and the electric field intensity between them is 1.92 x 106 N/C, downward, how far above the ground is the bottom of the cloud?

4) You charge up your pet pit bull by rubbing him on the living room carpet, and you bring him close to the neighbor's cat, to which you have previously given a charge of +3.50 x 10-3 C. (Why, you ask? There's nothing good on TV.) a. If the force acting between them when they are 1.35 m away from each other is an attractive force of 95100 N, what is the charge on the pit bull?

b. Calculate the electric field intensity at a point midway between the dog and the cat.

c. Calculate the potential difference between the dog-cat combination.

ANSWERS: 1. 2.55 x 10-5 V 2. 147 N/C 3. 625 m 4. a. -5.50 x 10-3 C b. 1.78 x 108 N/C, toward pit bull c. 2.40 x 108 V