A coil of self-inductance L is connected in series with a bulb B and an AC source. Brightness of bul

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7.Alternating Current

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A coil of self-inductance $L$ is connected in series with a bulb $B$ and an $AC$ source. Brightness of the bulb decreases when

number of turns in the coil is reduced.

a capacitance of reactance $X_c = X_L$ is included in the same circuit.

an iron rod is inserted in the coil.

frequency of the $AC$ source is decreased.

(AIPMT-2013)

Solution

The situation is as shown in the figure.

As the iron rod is inserted, the magnetic field inside the coil magnetizes the iron increasing the magnetic field inside it. Hence, the inductance of the coil increases. Consequently, the inductive reactance of the coil increases. As a result, a larger fraction of the applied $AC$ voltage appears across the inductor, leaving less voltage across the bulb. Therefore, the brightness of the light bulb decreases.

Standard 12

Physics

The equation of current in a purely inductive circuit is $5 \sin \left(49 \pi t-30^{\circ}\right)$. If the inductance is $30\,mH$ then the equation for the voltage across the inductor, will be.$\left\{\right.$ Let $\left.\pi=\frac{22}{7}\right\}$

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(JEE MAIN-2022)

An alternating voltage is connected in series with a resistance $R$ and an inductance $L$ If the potential drop across the resistance is $200\, V$ and across the inductance is $150 \,V,$ then the applied voltage is…….$V$

easy

An inductive circuit contains a resistance of $10 \,ohm$ and an inductance of $2.0\, henry$. If an ac voltage of $120 \,volt$ and frequency of $60\, Hz$ is applied to this circuit, the current in the circuit would be nearly……$amp$

medium

An inductor and a resistor in series are connected to an $A.C$. supply of variable frequency. As the frequency of the source is increased, the phase angle between current and the potential difference across $L$ will

easy

(AIIMS-2010)

For $L – R$ circuit, the time constant is equal to

medium

A coil of self-inductance $L$ is connected in series with a bulb $B$ and an $AC$ source. Brightness of the bulb decreases when

Solution

Similar Questions

The equation of current in a purely inductive circuit is $5 \sin \left(49 \pi t-30^{\circ}\right)$. If the inductance is $30\,mH$ then the equation for the voltage across the inductor, will be.$\left\{\right.$ Let $\left.\pi=\frac{22}{7}\right\}$

An alternating voltage is connected in series with a resistance $R$ and an inductance $L$ If the potential drop across the resistance is $200\, V$ and across the inductance is $150 \,V,$ then the applied voltage is…….$V$

An inductive circuit contains a resistance of $10 \,ohm$ and an inductance of $2.0\, henry$. If an ac voltage of $120 \,volt$ and frequency of $60\, Hz$ is applied to this circuit, the current in the circuit would be nearly……$amp$

An inductor and a resistor in series are connected to an $A.C$. supply of variable frequency. As the frequency of the source is increased, the phase angle between current and the potential difference across $L$ will

For $L – R$ circuit, the time constant is equal to

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