Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. To assure the same voltage is available to all devices; circuits are wired in

ID: 2263507 • Letter: 1

Question

1.       To assure the same voltage is available to all devices; circuits are wired in series / parallel / neither.

2.       In a series circuit, as resistance (lamps) are added, the current in the circuit increases / decreases / remains the same.

3.       In a parallel circuit, as resistance is added, the voltage drop at each lamp increases / decreases / remains the same.

4.       In a parallel circuit, as resistance is added, the current in the circuit increases / decreases / remains the same.

5.       A flashlight bulb with a potential difference of 6.0 V across it has a resistance of 8.5 W. How much current is

in the bulb filament? ______________

6.       Suppose three flashlight bulbs each with a resistance of 8.5? are connected in series with a 6 V battery.  

How much current is in each bulb? ______________

7.       Suppose three flashlight bulbs each with a resistance of 8.5? are connected in parallel with a 6 V battery.  

How much current is in each bulb? ______________

Explanation / Answer

1) To assure the same voltage is available to all devices; circuits are wired in parallel.
Why:
Voltage is same across the parallel circuits and current is divided.
In series circuit, current is same across all devices and voltage is divided between them.

2)In a series circuit, as resistance (lamps) are added, the current in the circuit decreases.
Why:
V = IR.
As you can see in this ohm's law, current is inverself proportional to resistance.
Thus, in series circuit, as the resistance is increased, current decresases.

3)In a parallel circuit, as resistance is added, the voltage drop at each lamp remains the same.
Why:
In a parallel circuit, the voltage remains same across all the devices and the current is divided.
Thus, if a new resistance is added, the voltage 'across each device' remains the same.

4)In a parallel circuit, as resistance is added, the current in the circuit increases.
Why:
Again, by the V=IR (ohm's law), we find that current is inversely proportional to resistance.
When resistances are connected in parallel, their effective resistance decreases. Thus, as resistance decreases, the curent in the circuit increases.

5)
V = 6V, R = 8.5 ohms
From ohm's law , V = IR , I = V/R
I = 6/8.5 = 0.7058 A

6)
three resistances are connected in series. Thus effective resistance, Re = R1+ R2+ R3
Re = 3*8.5 = 25.5 ohms
Now, from ohm's law, I=V/R
I = 6/25.5 = 0.235 A

7)
three resistances are connected in parallel.
The voltage across all bulbs are same.
From ohm's law, I = V/R
I = 6/8.5 = 0.7058 A

Hope, I solved all you doubts too. If you have any more doubts, comment and I can help you.
Cheers!