Question
Explain why the reactance offered by an inductor increases with increasing frequency of an alternating voltage.
✓
Answer
The inductive reactance is given by $\text{X}_\text{L}=2\pi\text{fL}$, XL is proportional to the frequency and current is inversely proportional to the reactance. An inductor opposes the flow of current through it by developing a back emf according to Lenz’s law. If the current is decreasing, the polarity of the induced emf will be so as to increase the current and vice-versa.
Since, the induced emf is proportional to the rate of change of current.
Since, the induced emf is proportional to the rate of change of current.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
- Three point charges q, -4q and 2q are placed at the vertices of an equilateral triangle ABC of side ‘l’ as shown in the figure. Obtain the expression for the magnitude of the resultant electric force acting on the charge q.
- Find out the amount of the work done to separate the charges at infinite distance.
- How does one explain the emission of electrons from a photosensitive surface with the help of Einstein's photoelectric equation?
- The work function of the following metals is given: Na 2.75 ev, K = 2.3 eV, Mo = 4.17 eV and Ni = 5.15 eV. Which of these metals will not cause photoelectric emission for radiation of wavelength 3300 Å from a laser source placed 1 m away from these metals? What happens if the laser source is brought nearer and placed 50 cm away?
According to the station clocks, two babies are born at the same instant, one in Howrah and other in Delhi.
- Who is elder in the frame of 2301 Up Rajdhani Express going from Howrah to Delhi?
- Who is elder in the frame of 2302 Dn Rajdhani Express going from Delhi to Howrah.
Obtain the binding energy (in MeV) of a nitrogen nucleus $(^{14}_7\text{N})$, given m $(^{14}_7\text{N})$ = 14.010307 u
→How are electromagnetic waves produced? What is the source of energy carried by a propagating electromagnetic wave? Identify the electromagnetic radiations used:
- In remote switches of household electronic devices.
- As diagnostic tool in medicine.
What is the de Broglie wavelength of a nitrogen molecule in air at 300 K? Assume that the molecule is moving with the root-meansquare speed of molecules at this temperature. (Atomic mass of nitrogen = 14.0076 u).
- Distinguish between a conductor and a semi conductor on the basis of energy band diagram.
- The following figure shows the input waveforms (A, B) and the output waveform (Y) of a gate. Identify the gate, write its truth table and draw its logic symbol.
Consider the situation of the previous problem. Define displacement resistance $\text{R}_\text{d}=\frac{\text{V}}{\text{i}_\text{d}}$ of the space between the plates, where V is the potential difference between the plates and id is the displacement current. Show that Rd varies with time as $\text{R}_\text{d}=\text{R}\big(\text{e}^{\text{t}/\tau}-1\big)$
→A partially plane polarised beam of light is passed through a Polaroid. Show graphically the variation of the transmitted light intensity with angle of rotation of the Polaroid.
The work function of a metal is 2.5 x 10 -19J.
- Find the threshold frequency for photoelectric emission.
- If the metal is exposed to a light beam of frequency 6.0 x 10-14 Hz, what will be the stopping potential?