9

An electron has a mass  and a charge .  How much work is done by an electric field, which moves the electron Starting from rest over a distance of

0.300 m through a potential difference of ?

 

A.

C.

 

 

 

 

B.

D.

 

 

So the Correct Answer is B !

10

A rail gun uses an electric potential difference to launch charged objects.  Consider using this to launch a satellite into orbit about the Earth.  The mass of a smaller satellite is .  It needs to reach geosynchronous orbit, which is  above sea level.  Let us assume the satellite can have  on it without damaging the satellite.  What is the potential difference required to accelerate the satellite to launch it for this orbit?  Is the ground the low or high potential point?  Ignore air resistance!

 

A.

, Ground is Low

C.

, Ground is Low

 

 

 

 

B.

, Ground is High

D.

, Ground is High

 

Since the satellite is positively charged, the ground must be positive compared to the end of the potential difference to push the satellite up!

 

 

 

 

So Correct answer is D !

11

Suppose you could transfer the kinetic energy of a car (mass ) travelling at a speed  to an onboard  capacitor.  What would the potential difference be across the capacitor if all the energy were transferred?

 

A.

B.

C.

 

D.

 

 

Solve for V

 

 

 

So Correct Answer is C !

12

A parallel plate capacitor has a dielectric slab with  in between the plates.  The capacitance of the capacitor with the dielectric inserted is .  The capacitor is fully charged by a 12.0 V power source and then the power supply is disconnected.  The dielectric slab is then removed.  What is the change in the potential difference across the plates of the capacitor?

 

A.

B.

C.

 

D.

 

 

Since the battery is removed, charge is constant on the plates.

 

And we know

so

 

and

The change in potential is

 

 

So Correct Answer is A !

 

 

 

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This page last updated on September 18, 2020