A plastic rod that has been charged to −15 nC touches a metal sphere. Afterward, the rod's charge is −10 nC. b. How many charged particles were transferred?

Verified step by step guidance

1. Identify the initial charge of the plastic rod and the final charge of the plastic rod after touching the metal sphere. Initial charge = -15 nC, Final charge = -10 nC.
2. Calculate the change in charge of the plastic rod by subtracting the final charge from the initial charge. Change in charge = Initial charge - Final charge.
3. Understand that the change in charge represents the amount of charge transferred to the metal sphere. This is because charge conservation dictates that the total charge before and after contact must be the same.
4. Convert the charge transferred into the number of electrons. Use the charge of a single electron, which is approximately -1.6 x 10^{-19} Coulombs.
5. Divide the total charge transferred by the charge of one electron to find the number of electrons transferred. Number of electrons = Total charge transferred / Charge of one electron.

Key Concepts

Charge Conservation

Charge conservation is a fundamental principle in physics stating that the total electric charge in an isolated system remains constant over time. When two objects come into contact, charge can be transferred between them, but the overall charge before and after the interaction must be equal. This principle helps in understanding how charges redistribute when conductive materials interact.

Elementary Charge

The elementary charge is the smallest unit of electric charge, denoted as 'e', approximately equal to 1.6 x 10^-19 coulombs. Charged particles, such as electrons and protons, carry this fundamental charge. In the context of the question, knowing the value of the elementary charge allows us to calculate the number of charged particles transferred during the interaction between the charged rod and the metal sphere.

Conductors and Charge Transfer

Conductors are materials that allow the flow of electric charge, typically due to the presence of free electrons. When a charged object, like the plastic rod, touches a conductor, such as a metal sphere, charge can move from one to the other until they reach an equilibrium state. This transfer of charge is crucial for understanding how the final charge on both objects is determined after contact.