In a series L-C-R circuit the voltage across resistance , capacitance and inductance is 10 V each. If the capacitance is short circuited, the voltage across the inductance will be
A. 10/`sqrt 2` V
B. 10 V
C. 10`sqrt 2` V
D. 20 V
Correct Answer - A
`X_C` = `X_L` = R
V = `sqrt (V_R^(2) + (V_L - V_C)^(2))` but `V_L` = `V_C`
`therefore` V = `V_R` = 10
When capacitor is short circuited , `V_C` = 0
and `V_R` = `V_L`
`therefore` V = `sqrt V_(R)^(2) + V_(L)^(2)` or 10 = `sqrt 2V_L`
`thereforeV_L = 10/sqrt 2` V .
Condition of resonance in a series LCR circuit:
`omegaL=1/(omegaC)`
where `omega`= angular frequency of the source, L=self inductance of the coil and C=capacitance.
Accordingly to the question, electric current and...
In a series LR circuit, power factor `(P_1)=R/Z`
Here, Z =impedance = `sqrt(R^2+X_L^2)`
Here, `Z=sqrt(R^2+R^2)=sqrt2R`
`thereforeP_1=1/sqrt2`
In a series LCR circuit power factor `(P_2)=R/Z`
where,`Z=sqrt(R^2+(X_L-X_C)^2)=R`
`thereforeP_2=1`
Hence,`P_1/P_2=1/sqrt2`
In L-R series cirucit current lags the voltage by an angle,
`phi = tan^(-1)(X_(L)/R)`
Here, `phi = pi/4`
`X_(L) = R` or `omegaL=R` `[omega=314 rad s^(-1)`
`therefore` 314 L =...
The rms value of voltage across the source, `V_(rms) = V_(0)/sqrt(2)`
comparing the given equation with general equation,
`V_(0) = 100sqrt(2),omega=1000rads^(-1)`
Also, R=`1000Omega`, C=`1muF= 1xx10^(-6)`F
L=2H
`V_(rms)=(100sqrt(2))/(sqrt(2)) = 100V`
`therefore...
Correct Answer - A
Given, the potential difference across each element is same i.e., 20V, so the circuit is at resonance and we have
`V=V_(R)=20V`
If the value of R is...
`X_(L)=2pifL` and `X_(C)=1/(2pifC)`
(i)When `f gt f_(r),X_(L)` is large and `X_(C)` is small.The circuit is induction current lags behind the applied voltage.
(ii)When `fltf_(r),X_(L)` is small and `X_(C)` is large.The...