Tuesday, April 12, 2011

FAQs

1. What is a) Current b)Voltage c) Resistance?
Ans: a) Flow of electric charge in a medium b)Energy carried by the charge c) Force that opposes the flow of electric charge
2. What are active and passive elements?
Ans: Active elements are capable of delivering power, while passive elements are capable of receiving, and possibly storing, power.
3. What is the difference between ac and dc current?
Ans: In DC(Direct current), the electrons flow steadily in a single direction, or "forward." In AC (Alternating Current), electrons keep switching directions, sometimes going "forwards" and then going "backwards."
4. What is a Spectrum?
Ans: Range of all possible frequencies of electromagnetic radiation.
5. What is a filter?
Ans: A circuit designed to selectively filter a frequency or a range of frequencies is called a filter.
6. What is dependent and independent source?
Ans: A dependent source maintains an output (fixed or varying with time) which is affected by any other quantity.
An independent source  maintains an output (fixed or varying with time) which is not affected by any other quantity.
7. What is Power and What is its relation to Current and voltage?
8. What is the difference between voltage and induced e.m.f.?
9. What is a) Ohms law b) KVL
c) KCL d) Thevenins Theorem
e) Nortons Theorem f) Superposition Theorem?
Ans:
a) Ohms law states that the voltage is directly proportional to current, the proportionality constant being resistance. (V= I.R)
b) KVL states that the algebraic sum of the voltages between successive nodes in a closed path in a circuit is equal to zero.
c) KCL states that the algebraic sum of the currents in all the branches that converge in a common node is equal to zero.
10. What is the difference between series and parallel connection?
11. What is resistivity?
Ans: Resistivity = (Resistance x Cross-sectional area)/ Length
ρ = R.A/L