2. Fully charged capacitor in an RC circuit is allowed to discharge. If the capa

Question

2. Fully charged capacitor in an RC circuit is allowed to discharge. If the capacitor reaches onequarter charge in 4.24 s, what is the time constant of this circuit? a) 12.4 s b) 8.88 s c) 3.06 s d) 4.24 s e) 0.555 s 3. A 342 m long wire carrying a current of 2.88 A is embedded in a 23.9 mT magnetic field such that it experiences a maximum force from the magnetic field. What is the magnitude of this maximum force? a) 3.29 N b) 68.8 N c) 4.97 N d) 985 N e) 23.5 N 4. A battery has an emf of 2.40 V. If this battery produces a voltage of 2.22 V when a current of 0.122 A is being drawn from it, what is the internal resistance of this battery? a) 19.7 b) 0.122 c) 2.40 d) 18.2 e) 1.48

Explanation / Answer

2)

answer is C

Q=Qo/4

Q=Qo*e^(-t/T)

Qo/4 =Qoe^(-4.24/T)

1/4 =e^(-4.24/T)

ln(0.25)=-4.24/T

-1.386=-4.24/T

T=3.06 s

3.)

answer is E

F=BILsin(x)

since it experiences maximum force sinx=1

F=BIL =23.9*10^-3*2.88*342

F=23.5N

4)

answer is E

internal reistance

r=(E-V)/I =(2.4-2.22)/0.122

r=1.48 ohms

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

---

---

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