OTRL Problem 15 (5 pts): A parallel plate capacitor can store an energy of 50 J

Question

OTRL Problem 15 (5 pts): A parallel plate capacitor can store an energy of 50 J when a voltage Vis applied across the two plates. Now, someone inside the capacitor to half of its original value. A voltage 2V is then used to charge up the capacitor. What will be the energy stored inside the capacitor after it is charged? modifies the capacitor by reducing the distance (d) between the two plates (Hint: E = 1 CV2) A) 25 J 50 J Cy 100J D) 200 J E) 400 J Problem 16 (5 pts): A resistor, a charged capacitor, and an open switch are all connected in series. The switeh is closed at time t-0 s. Which one of the following is a correct statement about the circuit? A) Current flows through the circuit even after the capacitor is essentially fully discharged B) The potential difference across the resistor is always equal to the potential difference across the capacitor C) The potential difference across the capacitor remains constant D) Once the capacitor is essentially fully discharged, there is no current in the circuit. Problem 17 (5 pts); The length and radius certain wire is doubled. What is the new resistance of this wire? A) Increased by a factor of4 B)Increased by a factor of 2 Reduced by a factor of 2 D) Reduced by a factor of4 E Reduced by a factor of 8

Explanation / Answer

15.

Given

C1 =C ,C2=(1/2)C

and V1=V ,V2=2V

Energy stored in capacitor

E=(1/2)CV2

=>E2/E1=(C2/C1)(V2/V1)2

E2=50*(1/2)*22

E2=100 J

16.

Answer is D

Once the capacitor is fully charged capacitor will act as open circuit ,so that no current flows in the circuit.

17.

Answer is C

Resistance of a wire is given by

R=pL/(pi*r2)

Given L2=2L1

and r2=2r1

=>R2/R1 =(L2/L1)(r1/r2)2

R2=R1*(2)*(1/2)2

R2=R1/2

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.