Current Electricity(6Q): Resistances in series and parallel

1- ) a string of Christmas-tree lights is frequently made of miniature lamps connected in series. For an 8-lamp, 120- volt set what is the voltage across each lamp? If one lamp were removed, what would happen? The voltage across the empty socket becomes equal to the line voltage. Why is this?

2- ) a piece of copper wire is cut into 10 equal parts. These parts are connected in parallel. How will the combined resistance of the parallel combination compare with the original resistance of the single wire?

3 - ) a wire 200 cm long has a resistance of 16.0 ohms. It is connected in series with resistance box of 8.00 ohms to battery having a terminal voltage of 8.00 volts. A poorly calibrated voltmeter connected across 150 cm of the wire reads 3.84 volts. What is the percentage error of the reading of the voltmeter?

4 - ) Sketch the outline of a cube. Imagine that each of the 12 edges represents a conductor having a resistance of 1.0 ohm. What is the resistance between corners diagonally opposite each other?

5 - ) a bank of three resistors in parallel is connected in series with a 3.00 ohm resistor and a battery of negligible internal resistance. The parallel group has resistances of 5.00 , 8.00, and 12.0 ohm resistor, what must be the emf of the battery ?

6 - ) What would the resistance of a power line have to be in order that the line drop shall not exceed 2% of the rated voltage of 120 volts when the current is changed from zero to 40 amp?

Solution Summary

Six good question to learn resistances in series and parallel and mix combinations and the current and power in that.

See attached circuit. Note current source is 2A,Resistors are 2 Ohms, Inductor 2H.
Assume that the switch has been open for a long time and that it closes at t=0 sec. The switch remains closed thereafter. How do I solve for Vx(t) and Ix(t)?

A 60.0 ohm resistor is connected in parallel with a 115.0 ohm resistor. This parallel group is connected in series with a 15.0hm resistor. The total combination is connected across a 15.0-V battery. Find the currentand power in the 115 ohm resistor.

I need some help with these two problems:
9. Consider the shown below. If we make the nichronic wire longer, what happens to the:
- (A) Equivalent resistance of the bulb (bulb B + wire) combination?
- (B) Current through Bulb A?
- (C) Voltage across Bulb B?
- (D) Voltage across Bulb A?
- (E) Current through Bulb B?
In eac

Resistances in series can be reduced to a unique resistance R such that
eq(1) R= r1 + r2 +...+ rn
in Parallel , we have
eq (2) 1/ (1/r1 +1/r2 +...+ 1/rn)
For the pulleys , to reduce the effort to keep a block and tackle (which has a mass M at he end) in equilibrium , the necessary force F to

Three capacitors each with capacitance C and a parallel combination of two resistances R each are connected in series with an ideal battery of emf V as in figure.
a) What is the time constant of the circuit?
b) If the switch is closed at time t = 0; find an expression for the current in the circuit as a function of time.
c)

Table 1. Resistor values for stated value and measured value for R1 and R2 in Ohms.
R1
(Ω) R2
(Ω)
Stated Value 360 180
Measured Value 362 184
Table 2. Measured Currents and Voltages for seriesandparallel configuration with calculated resistances.
Configuration I
(mA) I1
(mA) I2
(mA) V
(V) V1
(V) V2
(V) R
(

See the attached file.
You are probably familiar with "three-way" light builds, such as 1100/200/300W bulbs which have two filaments. As you turn the switch to its various settings the 100-W filament filament comes on by itself, then the 200-W filament comes on by itself, and then both filaments come on (connected in parallel)