Log In Start studying!

Select your language

Suggested languages for you:
Answers without the blur. Sign up and see all textbooks for free! Illustration

Q15P

Expert-verified
Fundamentals Of Physics
Found in: Page 740

Answers without the blur.

Just sign up for free and you're in.

Illustration

Short Answer

In Fig. 25-31, a 20.0 V battery is connected across capacitors of capacitances C1=C6=3.00 μF and C3=C5=2.00C2=2.00C4=4.00 μF What are (a) the equivalent capacitance Ceq of the capacitors and (b) the charge stored by Ceq? What are (c) V1 and (d) role="math" localid="1661748621904" q1 of capacitor 1, (e) role="math" localid="1661748675055" V2 and (f) q2of capacitor 2, and (g) V3 and (h) q3of capacitor 3?

a) The equivalent capacitance is Ceq=3 μF

b) The charge stored by role="math" localid="1661748823028" Ceq is q=60 μC

c) The value of V1 is V1=10 V

d) The charge of the capacitor 1 is q1=30 μC

e) The value of V2 is V1=10 V

f) The charge of the capacitor 2 is q2=20 μC

g) The value of V3 is V3=5 V

h) The charge q3 of the capacitor 2 is q3=20 μC

See the step by step solution

Step by Step Solution

Step 1: Given

The potential of the battery is V = 20 V

C1=C6=3 μFC3=C5=4 μFC2=C4=2 μF

Step 2: Determining the concept

Find the equivalent capacitance of the combination of different capacitors using the formula for equivalent capacitance connected in a series and in parallel. From the equivalent capacitance, find the charge stored by it. Find the potential difference and the charge stored across the capacitors using the formula for capacitance.

Formula:

q = CV

For parallel combination,Ceq=Cjj=1n

For series combination,1Ceq=1Cjj=1n

Where C is capacitance, V is the potential difference, q is the charge on the capacitor

Step 3: (a) Determining the equivalent capacitance

To find the equivalent capacitance, first, consider the capacitorsC3 and C5 connected them in a series. Find the equivalent capacitance for this combination by using the formula,

1Ceq=1Cjj=1n1C35=1C3+1C5 =C5+C3C3C5 =4 μF+4 μF4 μF×4 μF =12 μFC35=2 μF

Thus, equivalent capacitance is 2 μF.

This combination is then connected in parallel with C2 and C4. The resulting equivalent capacitance can be found by using the formula,

Ceq=Cjj=1nC=C35+C2+C4 =2 μF+2 μF+2 μF =6 μF

This is now in a series with another combination that consists of capacitors C1 and C6 in parallel. Find the equivalent capacitance for C1 and C6.

C'=C1+C6 =3 μF+3 μF =6 μFp;1

Thus, the equivalent capacitance of the circuit is,

Ceq=CC'C+C' =6 μF×6 μF6 μF+6 μF =36 μF12 =3 μF

Hence, the equivalent capacitance is Ceq=3 μF

Step 4: (b) Determining the charge stored by Ceq

The potential difference supplied by the battery is 20 V, then the total charge stored by the equivalent capacitor is,

q=CeqV =3 μF×20 V =3×10-6 F×20 V =60×10-61 μC10-6 C =60 μC

Hence, the charge stored by Ceq is q=60 μC

Step 5: (c) Determining the value of V1

The potential difference across C1 is given by,

V1=CVC+C' =6 μF×20 V6 μF+6 μF =120 V12 =10 V

Hence, the value of potential across C1 is V1=10 V

Step 6: (d) Determining the charge  q1 of the capacitor 1

The charge carried by C1 is,

q1=C1V1 =3 μF×10 V =30 μC

Hence, the charge of the capacitor 1 is q1=30 μC

Step 7: (e) Determining the value of V2

The potential difference across C2 can be calculated as,

V=V1+V2V2=V-V1 =20 V-10 V V =10 V

Hence, the value of V2 is V2=10 V

Step 8: (f) Determining the charge q2 of the capacitor

The charge carried by C2 is,

q2=C2V2 =2 μF×10 V =20 μC

Hence, the charge q2 of the capacitor 2 is q2=20 μC

Step 9: (g) Determining the value of V3

Since the potential difference V2 is divided equally between C3 and C5. The potential difference across C3 is,

V3=V22 =10 V2 =5 V

Hence, the value of V3 is V3=5 V

Step 10: (h) Determining the charge q3 of the capacitor 3

The charge carried by q3 is,

q3=C3V3 =4 μF×5 V =20 μC

Hence, the charge q3 of the capacitor 3 is q3=20 μC

Therefore, find the equivalent capacitance using the formula for equivalent capacitance connected in series and parallel. The potential difference and the charge stored across the capacitors can be found using the formula for capacitance.

Recommended explanations on Physics Textbooks

94% of StudySmarter users get better grades.

Sign up for free
94% of StudySmarter users get better grades.