a. What is the current flowing in the series circuit?
c. In the circuit described in part (b) above, how much power is dissipated in the 200 ohms resistor?
d. A telephone handset has a resistance of 600 ohms. It is connected to the local telephone exchange at a distance of 5 km by a twisted pair that has a loop resistance of 200 ohms per km. The telephone exchange has a 48.0 V battery that is connected to the twisted pair through a 400 ohms resistor. What is the DC current through the handset when it is off-hook?
Please see the attachment as well for clear symbols and drawing in (d).
(a) As it is a series circuit with just resistance we can say that by Ohm's law
Voltage (V) = Current (I) x Total Resistance (R (tot))
i.e. V = IR(tot) (1)
We are asked to find the current so we rearrange (1) to make I the subject when we do this we get (2).
I = V/R(tot) (2)
Now total resistance is sum of series resistance so we can deduce
R(tot) = 100 + 200 + 60 Ohms = 360 Ohms
Now we ...
A series circuit is examined with three given series pure resistances. A battery is connected of known DC voltage and the current flowing in the series circuit deduced. A sine wave generator of know amplitude and frequency replaces the battery and the RMS current that flows and the power dissipated is deduced. A telephone line of known parameters is given and the DC current that flows through the handset for such a system is deduced.