Basic Electrical Engineering Questions and Answers – Alternating Current in a Capacitive Circuit

«
»

This set of Basic Electrical Engineering Problems focuses on “Alternating Current in a Capacitive Circuit”.

1. What is the resonance frequency of ac circuit?
a) 1/√LC
b) √(L/C)
c) √LC
d) LC
View Answer

Answer: a
Explanation: At resonance, XL=XC
ωL=1/ωC
ω=1/√LC.

2. What is impedance at resonance?
a) maximum
b) minimum
c) zero
d) cannot be determined
View Answer

Answer: b
Explanation: At resonance, XL=XC
Z2=R2+(XL-XC)2
Z=R So Z is minimum at resonance.

3. What is the value of impedance at resonance?
a) XL
b) XC
c) R
d) 0
View Answer

Answer: c
Explanation: At resonance, XL=XC
Z2=R2+(XL-XC)2
Z=R So Z is minimum at resonance.
advertisement
advertisement

4. What is φ in terms of voltage?
a) φ=cos-1V/VR
b) φ=cos-1V*VR
c) φ=cos-1VR/V
d) φ=tan-1V/VR
View Answer

Answer: c
Explanation: Form the voltage triangle, we get cosφ= VR/V.
Hence φ=cos-1VR/V.

5. What is tanϕ for RC circuit?
a) XC/R
b) XL/R
c) R/Z
d) Z/R
View Answer

Answer: a
Explanation: From the impedance triangle, height gives capacitive reactance and base gives resistance.
tanϕ=XC/R.

6. What is the resonance condition?
a) When XL>XC
b) When XL<XC
c) When XL=XC
d) When XC=infinity
View Answer

Answer: c
Explanation: The current is in phase with the voltage when the capacitive reactance is in equal to the inductive reactance. This is known as resonance condition.

7. What is the frequency in resonance condition?
a) Minimum
b) Maximum
c) Cannot be determined
d) Zero
View Answer

Answer: b
Explanation: At resonance condition, the frequency is maximum since the inductive reactance is equal to the capacitive reactance. XL=XC.
advertisement

Sanfoundry Global Education & Learning Series – Basic Electrical Engineering.

To practice all areas of Basic Electrical Engineering Problems, here is complete set of 1000+ Multiple Choice Questions and Answers.

advertisement

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

Subscribe to his free Masterclasses at Youtube & technical discussions at Telegram SanfoundryClasses.