Define:
(a) Inductive reactance
(b) Capacitive reactance
(c) Impedance
(a) Inductive reactance
(b) Capacitive reactance
(c) Impedance
Show Hint
Solution and Explanation
b. Capacitive Reactance (\( X_C \)): The opposition offered by a capacitor to alternating current, given by \( X_C = \frac{1}{\omega C} = \frac{1}{2\pi f C} \), where \( C \) is capacitance. Unit: ohm.
c. Impedance (\( Z \)): The total opposition to alternating current in a circuit with resistance, inductance, and capacitance, given by \( Z = \sqrt{R^2 + (X_L - X_C)^2} \). Unit: ohm.
Answer: Inductive reactance opposes current in inductors; capacitive in capacitors; impedance is total AC opposition.
Top Questions on Electromagnetism
- Assertion (A): A charged particle is moving with velocity \( v \) in \( x \)-\( y \) plane, making an angle \( \theta \) (\( 0<\theta<90^\circ \)) with \( x \)-axis. If a uniform magnetic field is applied in the region, along \( y \)-axis, the particle will move in a helical path with its axis parallel to \( x \)-axis.
Reason (R): The direction of the magnetic force acting on a charged particle moving in a magnetic field is along the velocity of the particle.- CBSE CLASS XII - 2025
- Physics
- Electromagnetism
Draw the pattern of the magnetic field lines for the two parallel straight conductors carrying current of same magnitude 'I' in opposite directions as shown. Show the direction of magnetic field at a point O which is equidistant from the two conductors. (Consider that the conductors are inserted normal to the plane of a rectangular cardboard.)
- CBSE Class X - 2025
- Science
- Electromagnetism
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Choke coil is simply a coil having a large inductance but a small resistance. Choke coils are used with fluorescent mercury-tube fittings. If household electric power is directly connected to a mercury tube, the tube will be damaged.
Reason (R): By using the choke coil, the voltage across the tube is reduced by a factor \( \frac{R}{\sqrt{R^2 + \omega^2 L^2}} \), where \( \omega \) is the frequency of the supply across resistor \( R \) and inductor \( L \). If the choke coil were not used, the voltage across the resistor would be the same as the applied voltage.
In light of the above statements, choose the most appropriate answer from the options given below:
- JEE Main - 2025
- Physics
- Electromagnetism
Figure shows a current carrying square loop ABCD of edge length is $ a $ lying in a plane. If the resistance of the ABC part is $ r $ and that of the ADC part is $ 2r $, then the magnitude of the resultant magnetic field at the center of the square loop is:
- JEE Main - 2025
- Physics
- Electromagnetism
- An infinitely long wire has uniform linear charge density $ \lambda = 2 \, \text{nC/m} $. The net flux through a Gaussian cube of side length $ \sqrt{3} \, \text{cm} $, if the wire passes through any two corners of the cube, that are maximally displaced from each other, would be $ x \, \text{Nm}^2 \text{C}^{-1} $, where $ x $ is:
- JEE Main - 2025
- Physics
- Electromagnetism
Questions Asked in Maharashtra Class XII exam
- What is value of B called, when H = 0 is in the hysteresis loop?
- If \(|\vec{a}| = 5\), \(|\vec{b}| = 13\), and \(|\vec{a} \times \vec{b}| = 25\), then \(|\vec{a} \cdot \vec{b}|\) is equal to ........
- Maharashtra Class XII - 2025
- Vector Algebra
- Calculate the electric field intensity at a point just near the surface of a charged plane sheet, measured from its mid-point. [ \( \sigma = 8.85 \, \mu C/m^2 \) ]
- Maharashtra Class XII - 2025
- Electrostatics
- Identify ‘A’ and ‘B’ in the following reaction and rewrite the complete reaction : \[ \text{CH}_3\text{-CH=CH}_2 \xrightarrow[\text{Peroxide}]{\text{HBr}} \text{A} \xrightarrow[\text{-KBr}]{\text{alcoholic KCN}} \text{B} \]
- Maharashtra Class XII - 2025
- Organic Chemistry
- Divide the number 20 into two parts such that the sum of their squares is minimum.
- Maharashtra Class XII - 2025
- Optimization