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  • Figure 8.6 shows a capacitor made of two circular plates each of radius 12 cm, and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15 A.

     

    (a) Calculate the capacitance and the rate of charge of potential difference between the plates.

     

    (b) Obtain the displacement current across the plates.

     

    (c) Is Kirchhoff’s first rule (junction rule) valid at each plate of the capacitor? Explain.

Figure 8.6 shows a capacitor made of two | Class 12 Physics Chapter Electromagnetic Waves, Electromagnetic Waves NCERT Solutions

Q1.

Figure 8.6 shows a capacitor made of two circular plates each of radius 12 cm, and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15 A.

 

(a) Calculate the capacitance and the rate of charge of potential difference between the plates.

 

(b) Obtain the displacement current across the plates.

 

(c) Is Kirchhoff’s first rule (junction rule) valid at each plate of the capacitor? Explain.

Radius of each circular plate, r = 12 cm = 0.12 m

Distance between the plates, d = 5 cm = 0.05 m

Charging current, I = 0.15 A

Permittivity of free space, = 8.85 × 10−12 C2 N−1 m−2

(a) Capacitance between the two plates is given by the relation,

C

Where, A = Area of each plate = πr squared

Charge on each plate, q = CV

Where, V = Potential difference across the plates Differentiation on both sides with respect to time (t) gives:

Therefore, the change in potential difference between the plates is 1.87 ×109 V/s.

 

(b) The displacement current across the plates is the same as the conduction current. Hence, the displacement current, id is 0.15 A.

 

(c) Yes

Kirchhoff’s first rule is valid at each plate of the capacitor provided that we take the sum of conduction and displacement for current.

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Important Questions & Answers

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This question is important because it tests key concepts from the NCERT syllabus and is frequently asked in CBSE exams.

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What is the correct answer to: Figure 8.6 shows a capacitor made of two circular plates each of radius 12 cm, and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15 A.   (a) Calculate the capacitance and the rate of charge of potential difference between the plates.   (b) Obtain the displacement current across the plates.   (c) Is Kirchhoff’s first rule (junction rule) valid at each plate of the capacitor? Explain.?

Radius of each circular plate, r = 12 cm = 0.12 m

Distance between the plates, d = 5 cm = 0.05 m

Charging current, I = 0.15 A

Permittivity of free space, = 8.85 × 10−12 C2 N−1 m−2

(a) ...

How do you solve Figure 8.6 shows a capacitor made of two circular plates each of radius 12 cm, and separated by 5.0 cm. The capacitor is being charged by an external source (not shown in the figure). The charging current is constant and equal to 0.15 A.   (a) Calculate the capacitance and the rate of charge of potential difference between the plates.   (b) Obtain the displacement current across the plates.   (c) Is Kirchhoff’s first rule (junction rule) valid at each plate of the capacitor? Explain. step by step?

Step-by-step explanation:
• Radius of each circular plate, r = 12 cm = 0
• 12 m
•
• Distance between the plates, d = 5 cm = 0
• 05 m

What common mistakes should be avoided in this question?

Students often lose marks by skipping steps, writing incomplete explanations, or misunderstanding keywords used in the question.

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