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Creating Electric Fields
Measuring Electric Fields
Energy and Electric Potential
Uniform Electric Field
The Capacitor
100
This is the equation we use to measure the strength of the electric field.
What is E = F/q
100
If someone told you to measure an electric field with a test charge how would you do it?
Place the test charge in the electric field and measure the force, F, on it. The electric field strength is calculated by F/q.
100
If you apply a force, F, over a distance, d, this would be an example of __________.
What is work.
100
The SI unit of potential difference is the______.
What is volt.
100
For a given size and shape of an object, the ratio of charged stored to electric potential difference, q/V, is a constant called ________.
What is capacitance.
200
We use this particle to test the electric field. What is its name, charge, and magnitude?
What is a test charge. The magnitude is small so we don't disrupt the field.
200
An electric field is about 150 N/C downward. What is the direction of the force on a positively charged particle?
What is downward.
200
This is defined as the work done moving a positive test charge between two points in an electric field divided by the magnitude of the test charge.
What is electric potential difference, or voltage. V = W/q
200
Millikan's oil drop helped determine the __________.
What is charge of the electron.
200
The unit of capacitance is the _______.
What is the Farad.
300
The ________ is a vector quantity that relates the force on a test charge to the size of the charge.
What is the electric field.
300
Lines drawn to represent an electric field extend _______ a positive charge and ________ a negative charge.
What is away from, toward.
300
Whenever the electric potential difference between two points is zero, those positions are said to be at _________.
What is equipotential.
300
In a uniform electric field the potential is highest near the _______ plate and lowest near the ______ plate.
What is positive plate, negative plate.
300
A 27 micro-Farad capacitor has an electric potential difference of 45 V across it. What is the charge on the capacitor?
What is 1.2x10^-3 C.
400
According to Coulomb's law, the force on a test charge is ________ the test charge.
What is proportional to.
400
How does the electric field, E, at the test charge differ from the force, F, on it?
The field is a property of that region of space, and does not depend on the test charge used to measure it. The force depends on the magnitude and sign of the test charge.
400
What work is done when 3.5 C is moved though an electric potential difference of 4.5 V?
What is 15.75 Joules
400
Electric potential difference, Volts, is measured in_____ per ______.
What is Joules per coulomb.
400
How much charge is stored on a 0.47 micro-Farad capacitor when a potential difference of 12 V is applied to it?
What is 5.6x10^-6 C.
500
A positive test charge of 5.0x10^-6 C is in an electric field that exerts a force of 2.0x10^-4 N on it. What is the magnitude of the electric field at the location of the test charge.
What is 40 N/C
500
What happens to the strength of the electric field when the test charge is halved?
Nothing. The force on the test charge would also be halved and according to E = F/q, the electric field, E, would still be the same.
500
Two charged parallel plates are 1.5 cm apart. The magnitude of the electric field between the plates is 1800 N/C. What is the electric potential difference between the two plates?
What is 27 Volts
500
In a Millikan oil-drop experiment, a drop has been found to weight 2.4x10^-14 N. The parallel plates are separated by a distance of 1.2 cm. When the potential difference between the plates is 450 V, the drop is suspended, motionless. What is the charge on the oil drop?
What is 6.4x10^-19 C.
500
What is the charge on a 15.0 pico-Farad capacitor when it is connected across a 45.0-V source.
What is 6.75x10^-10 C.