Two 20 ohm resistors are connected in parallel and two 10 ohm resistors are connected in parallel. If these two combinations are
connected in series the equivalent resistance of the combination is: a) 20 ohm b) 10 ohm c) 15 Ohm d) 30 Ohm
1 answer:
C. 15Ω.
The circuit diagram is shown in the first image attached. To solve this problem we have to use the equivalent resistor conected in parallel Req = (R1*R2)/(R1+R2).
Calculating the equivalent resistor in the 20Ω resistor parallel arrangement:
RAeq = [(20*20)/(20+20)] Ω
RAeq = 400/40 Ω
RAeq = 10Ω
Calculating the equivalent resistor in the 10Ω resistor parallel arrangement:
RBeq = [(10*10)/(10+10)]Ω
RBeq = 100/20 Ω
RBeq = 5Ω
Both equivalent resistors are in series. So, in order to calculate the equivalent resistance of the combination:
Rtotal = RAeq + RBeq
Rtotal = 10Ω + 5Ω
Rtotal = 15Ω
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Answer:
a) the total electric potential is 2282000 V
b) the total electric potential (in V) at the point with coordinates (0, 1.50 cm) is 1330769.23 V
Explanation:
Given the data in the question and as illustrated in the image below;
a) Determine the total electric potential (in V) at the origin.
We know that; electric potential due to multiple charges is equal to sum of electric potentials due to individual charges
so
Electric potential at p in the diagram 1 below is;
Vp = V1 + V2
Vp = kq1/r1 + kq2/r2
we know that; Coulomb constant, k = 9 × 10⁹ C
q1 = 4.60 uC = 4.60 × 10⁻⁶ C
r1 = 1.25 cm = 0.0125 m
q2 = -2.06 uC = -2.06 × 10⁻⁶ C
location x2 = −1.80 cm; so r2 = 1.80 cm = 0.018 m
so we substitute
Vp = ( 9 × 10⁹ × 4.60 × 10⁻⁶/ 0.0125 ) + ( 9 × 10⁹ × -2.06 × 10⁻⁶ / 0.018 )
Vp = (3312000) + ( -1030000 )
Vp = 3312000 -1030000
Vp = 2282000 V
Therefore, the total electric potential is 2282000 V
b)
the total electric potential (in V) at the point with coordinates (0, 1.50 cm).
As illustrated in the second image;
r1² = 0.015² + 0.0125²
r1 = √[ 0.015² + 0.0125² ]
r1 = √0.00038125
r1 = 0.0195
Also
r2² = 0.015² + 0.018²
r2 = √[ 0.015² + 0.018² ]
r2 = √0.000549
r2 = 0.0234
Now, Electric Potential at P in the second image below will be;
Vp = V1 + V2
Vp = kq1/r1 + kq2/r2
we substitute
Vp = ( 9 × 10⁹ × 4.60 × 10⁻⁶/ 0.0195 ) + ( 9 × 10⁹ × -2.06 × 10⁻⁶ / 0.0234 )
Vp = 2123076.923 + ( -762962.962 )
Vp = 2123076.923 -792307.692
Vp = 1330769.23 V
Therefore, the total electric potential (in V) at the point with coordinates (0, 1.50 cm) is 1330769.23 V
