Problem 59A

Electricity In a series resistance−capacitance DC circuit, the instantaneous charge Q on the capacitor as a function of time (where t = 0 is the moment the circuit is energized by closing a switch) is given by the equation

Q(t) = CV(1 − e−t/RC),

where C, V, and R are constants. Further, the instantaneous charging current IC is the rate of change of charge on the capacitor, or IC = dQ/dt. Source: Kevin Friedrich.

a. Find the expression for IC as a function of time.

b. If C = 10−5 farads, R = 107 ohms, and V = 10 volts, what is the charging current after 200 seconds? (Hint: When placed into the function in part a the units can be combined into amps.)

Leslie Ogu CSCI 4531 09/06/2016 Chapter 2: Encryption Symmetric Encryption + The universal technique for providing confidentiality for transmitted or stored data + Also referred to as conventional encryption or singlekey encryption + Two requirements to use: + Need a strong encryption algorithm + Sender and receiver must have obtained copies of the secret key in a secure fashion and and must keep the key secure + Only alternative before publickey encryption in 1970’s + Still most widely used alternative + 5 Ingredients + Plaintext + Encryption algorithm + Secret key + Ciphertext