PH 202

Quiz # 03 (10 pts)

Name

Solution

A capacitor is charged up to a potential difference of and then disconnected from the power source. What is the amount of charge on the capacitor?

A.

B.

C.

D.

So Correct Answer is B !

A parallel plate capacitor is made of two large area plates () which are separated by a distance (). When there is nothing between the plates, the capacitance is . A power supply creates a potential difference () between the plates and then the power supply is removed. The space between the plates is then filled with water (). If you now measure the potential difference across the plates you would find it is?

A.

B.

C.

D.

With the power supply removed, Q, cannot change. Capacitance and Voltage do.

So we see

So Correct Answer is D !

A parallel plate capacitor has a potential difference of between the plates. When measured, the electric field is found to have a strength of . How far apart are the plates?

A.		C.
B.		D.

E Field between the plates of a capacitor can be found from expression

So solving for (drop – sign as it is directional) and recall

So Correct Answer is A !

A starter motor on a particular vehicle requires for . The potential difference across the battery terminals is . How much energy did the battery supply to engage the starter motor?

A.

B.

C.

D.

So the Correct Answer is A !

An average car battery has of charge in it. That means it can deliver of current for 1 hour, or of current for 2 hours, etc. Assuming all the current is in the form of electrons (), how many electrons are available to be delivered by the battery?

A.		C.
B.		D.

First find the total amount of charge that can be delivered.

Now determine how many electrons are required to make up that charge

Solve for N

So Correct answer is C !

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This page last updated on September 11, 2020