Electric Field Review

A proton is released from rest at the origin in a uniform electric field in the positive x direction with magnitude 850 N/C. What is the change in the electric potential energy of the proton–field system when the proton travels to x = 2.50 m? 

• 3.40 × 10-16 J 
• -3.40 × 10-16 J 
• 2.50 × 10-16 J 
• 4-2.50 × 10-16 J 

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An electron volt is

• the force acting on an electron in a field of 1 N/C 
• the force required to move an electron 1 meter 
• the energy gained by an electron in moving through a potential difference of 1 volt 
• the energy needed to move an electron through 1 meter in any electric field 

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NGSS.HS-PS3-5

A tiny sphere carrying a charge of 6.5 µC sits in an electric field, at a point where the electric potential is 240 V. What is the sphere’s potential energy?

• 2.7 x 10^-8 J 
• 6.5 x 10^-6 J 
• 1.6 x 10^-3 J
• 240 J 

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An electron moves from point i to point f, in the direction of a uniform electric field.  During this motion:

• the work done by the field is positive and the potential energy of the electron-field system increases
• the work done by the field is negative and the potential energy of the electron-field system increases
• the work done by the field is positive and the potential energy of the electron-field system decreases
• the work done by the field is negative and the potential energy of the electron-field system decreases

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NGSS.HS-PS3-1

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If 500 J of work are required to carry a 40-C charge from one point to another, the potential difference between these two points is: 

• 12.5 V 
• 20,000 V 
• 0.08 V 
• depends on the path 

The potential difference between two points is 100 V. If a particle with a charge of 2 C is transported from one of these points to the other, the magnitude of the work done is: 

• 200 J
• 100 J
• 50 J
• 2 J

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NGSS.HS-PS3-1

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During a lightning discharge, 30 C of charge move through a potential difference of 1.0 x 10⁸ V in 2.0 x 10^–2 s. The energy released by this lightning bolt is: 

• 1.5 ´ 10¹¹ J
• 3.0 ´ 10⁹ J 
• 6.0 ´ 10⁷ J 
• 3.3 ´ 10⁶ J

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An electron goes from one equipotential surface to another along one of the four paths shown below.  Rank the paths according to the work done by the electric field, from least to greatest.

• 1, 2, 3, 4
• 4, 3, 2, 1
• 1, then 3, then 4 and 2 tie
• 4 and 2 tie, then 3, then 1

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The electric field around an isolated electron has a certain strength 1 cm from the electron. The electric field strength 2 cm from the electron is 

• half as much. 
• the same. 
• twice as much. 
• one fourth times as much.

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NGSS.HS-PS2-4

A 2-C charge experiences a force of 40 N when put at a certain location in space. The electric field at that location is .

• 2 N/C. 
• 20 N/C
• 30 N/C. 
• 40 N/C.