some ac questions.

1) In LCR circuit , if (1/LC)<(R^2/4L^2) , the circuit would be :

a) oscillatory
b) dead beat
c) critically damped
d) none of these

2) A circuit has an inductance 10 mH, capacitance 0.1 \muF and resistance 1 K\Omegas. If an emf 105 volts is in the circuit , then which of the following is correct ?

a) circuit is oscillatory and final charge on capacitor is 0.01 C.

b) circuit is not oscillatory and final charge on capacitor is 0.01 C.

c) final charge on capacitor is 0.02 C

d) none of these.

8 Answers

19
Debotosh.. ·

ans 1> overdamped
here ω < R/2L

.....but i do not find it in any of the options(of course none of these),,,but is it dead bit?

1
aieeee ·

ya , u r right. but , i'm not sure hw dead beat is realised here ?
is dead beat only refering non - oscillatory ?

106
Asish Mahapatra ·

debo. .how do u get the condition for overdamp ...

24
eureka123 ·

Ans1 will be overdamped iff series circuit

1
aieeee ·

ya, but is critically damped different from overdamped ?

the answer is b) dead beat. but what does dead beat refer here ? only non-oscillatory ?

24
eureka123 ·

ya critically damped is diff from overdamped....saying in simple words...overdamped is bigger stage of damping than critically..

short on time..so pasting from wiki..
""Overdamped (ζ > 1): The system returns (exponentially decays) to equilibrium without oscillating. Larger values of the damping ratio ζ return to equilibrium slower.
Critically damped (ζ = 1): The system returns to equilibrium as quickly as possible without oscillating. This is often desired for the damping of systems such as doors.
Underdamped (ζ < 1): The system oscillates (with a slightly different frequency than the undamped case) with the amplitude gradually decreasing to zero.""

24
eureka123 ·

and i cant understand how ans is dead beat..

btw something on it here..
http://digitool.library.mcgill.ca/R/?func=dbin-jump-full&object_id=30251&local_base=GEN01-MCG02

24
eureka123 ·

btw the only time i read abt dead beat was in boards under topic eddy currents..

here is somethign more....(i have underlined imp thing)

again sorry for copy pasting all this

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