Electricity and Magnetism Answers

A sphere has with a charge of +6.4 milli-coulombs is placed on an insulating stand.
a. How many elementary charges does this represent?
b. Does this charged sphere have a lack of electrons or an excess of electrons relative to its neutral state? (Explain)

1. An electrically neutral glass rod is rubbed against a neutral piece of silk. During this process 2.0 x 1015 electrons are transferred from the rod to the silk.
a. How much charge (in coulombs) did the silk acquire?
b. What charge does the glass rod have after being rubbed on the silk? (explain)

For a long straight wire, if the current is halved and the distance from the wire is doubled, what will B be then?

A charge experiences a force of 4.3 x 10 -6 N in a uniform electric field of intensity 7.0 N/C. What is the charge?

A capacitor has a total charge of 6 μC stored. If it were possible to transfer this charge uniformly through a light with a current of 100 mA, how long would the light stay lit?

As an open train car rolls along a track, it is slowly filled with sand. Assume there is no friction, and that the car is just rolling along without receiving additional force. As the sand fills the car, what happens to the car's velocity?

Select one:
a. It increases, because momentum must be conserved and the mass of the car is increasing.
b. It decreases, but not because of any of the other reasons.
c. It decreases, because momentum must be conserved and the mass of the car is increasing.
d. It increases, but not because of any of the other reasons.
e. It decreases, because the frictional force increases as the mass increases.

Find the binding energy of helium 3 and helium 4

A 35.4 g bullet strikes a 18.0 kg stationary wooden block and embeds itself in the block. The block and the bullet fly off together at 13.3 m/s.



What was the initial velocity of the bullet?

A cannonball with a mass of 13.1 kg is fired from a cannon that has a mass of 907.2 kg. The cannonball is fired with a speed of 159.4 m/s, and it takes 0.0 seconds for the cannonball to leave the cannon.



Determine the recoil speed of the cannon.

A 7.4 kg bowling ball traveling at 12.91 m/s strikes a 2.9 kg bowling pin. The impact slows the bowling ball to 9.67 m/s.



Determine the impulse given to the pin.