A student connects a long air-cored coil of m | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) For $DC$ supply,the coil acts as a pure resistor $R$. Given $V = 100 \ V$ and $I = 25 \ A$,the resistance is $R = \frac{V}{I} = \frac{100}{25} = 4

Vedclass · Accepted Answer

$3$

Vedclass · Answer

(B) For $DC$ supply,the coil acts as a pure resistor $R$. Given $V = 100 \ V$ and $I = 25 \ A$,the resistance is $R = \frac{V}{I} = \frac{100}{25} = 4 \ \Omega$.For $AC$ supply,the coil acts as an $LR$ circuit with impedance $Z$. Given $V = 100 \ V$ and $I = 20 \ A$,the impedance is $Z = \frac{V}{I} = \frac{100}{20} = 5 \ \Omega$.The impedance $Z$ is related to resistance $R$ and inductive reactance $X_L$ by the formula $Z^2 = R^2 + X_L^2$.Substituting the values,$5^2 = 4^2 + X_L^2$.$25 = 16 + X_L^2 \Rightarrow X_L^2 = 25 - 16 = 9$.Therefore,the reactance $X_L = \sqrt{9} = 3 \ \Omega$.

$A$ student connects a long air-cored coil of manganin wire to a $100 \ V$ $DC$ supply and records a current of $25 \ A$. When the same coil is connected across a $100 \ V, 50 \ Hz$ $AC$ supply,the current reduces to $20 \ A$. The reactance of the coil is $...... \Omega$.

Similar Questions

$A$ resistor of $500 \Omega$ and an inductor of $0.5 \ H$ are connected in series with an $AC$ source given by $V = 100 \sqrt{2} \sin(1000 t)$. The power factor of the combination is:

$A$ lamp is connected in series with a capacitor and an $AC$ source. What happens if the capacitance of the capacitor is reduced?

To light a $50\,W, 100\,V$ lamp,it is connected in series with a capacitor of capacitance $C = \frac{50}{\pi \sqrt{x}} \mu F$ to a $200\,V, 50\,Hz$ $AC$ source. The value of $x$ is........

When $100 \, V$ $DC$ is supplied across a solenoid,a current of $1.0 \, A$ flows in it. When $100 \, V$ $AC$ is applied across the same coil,the current drops to $0.5 \, A$. If the frequency of the $AC$ source is $50 \, Hz$,then the impedance and inductance of the solenoid are:

In an $AC$ circuit,a resistance of $R \, \Omega$ is connected in series with an inductance $L$. If the phase angle between voltage and current is $45^o$,the value of inductive reactance will be:

Vedclass Test Series

Exam Paper Generator

Online Exam Module