An oil droplet with excess electrons is observed between two parallel electrodes spaced apart. The droplet hangs motionless if the upper electrode is more positive than the lower electrode. The density of the oil is . What is the radius of the droplet?
A drop will remain suspended between the plates, moving neither up nor down, if the electric field exerts an upward force on a charged drop that exactly balances the downward gravitational force. The forces balance when (m is mass of drop and q is charge on drop).
It was given to us that there is oil droplet of excess electrons between parallel plates which are apart.
Density of oil=
droplet consists of 15 excess electron means it will charge of 15 electrons
Equating forces acting on droplet:
Hence, radius of droplet is
To initiate a nuclear reaction, an experimental nuclear physicist wants to shoot a proton into a 5.50-fm-diameter 12C nucleus. The proton must impact the nucleus with a kinetic energy of 3.00 MeV. Assume the nucleus remains at rest.
a. With what speed must the proton be fired toward the target?
b. Through what potential difference must the proton be accelerated from rest to acquire this speed?
Your friend flies from Los Angeles to New York. She carries an accurate stopwatch with her to measure the flight time. You and your assistants on the ground also measure the flight time.a. Identify the two events associated with this measurement.b. Who, if anyone, measures the proper time?c. Who, if anyone, measures the shorter flight time?
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