# Why inductance is called electrical inertia?

The size of the induced electromotive force is proportional to the rate of change of theelectric current. ... The self-inductance of a coil, or simply its inductance, may thus be thought of as electromagnetic inertia, a property that opposes changes both in currents and in magnetic fields.

## Related questions

Answer : The voltage across an inductor is directly proportional to inductance (V=L*di/dt*I).And the voltage is Also directly proportion to frequency.

Description : Why is weightlessness experienced while orbiting the earth in space ships ? (1) Inertia (2) Acceleration (3) Zero gravity (4) Orbital motion

Description : The Newton’s First Law is also called as (1) Law of moments (2) Law of inertia (3) Law of energy (4) Law of momentum

Description : Why in electric motor or generator heating due to current involves dissipation of electrical energy?

Answer : In electric motor or generator heating due to current involves dissipation of electrical energy because as the current increases there will be I2R losses. More current flow means more the heat will be generated and as the temperature of conductor increase its resistance increases.

Description : why reactive ohm cannot converted electrical energy into heat?

Answer : Because it describes the resistance of element that store energy rather than dissipate energy as heat

Description : Why earthing is essential in electrical installation ? Explain any one type of earthing.

Answer : Following reasons earthing is essential in electrical installation :   1. To provide an alternative path for the leakage current to flow towards earth. 2. To save human life from danger of electrical shock ... G.I. pipe of size 19mm and funnel for pouring the water in earth pit when required.

Answer : The efficiency of transformer is Greater than electrical Machine because there is no rotational losses in transformer and there is no air gap losses in transformer so losses is less in transformer compare to electrical machine so efficiency is higher in case of transformer.

Description : why the electrical appliances are connected in parallel ?

Answer : If the appliances connected in series if one of the appliances fails to work other appliances also doesn't work because the current doesn't flow in the appliances.so ,we connect appliances in parallel that if any one of the appliances fails to work it doesn't effect other appliances .

Description : If the inertia constant H of a machine of 200 MVA is 2 p.u., its value corresponding to 400 MVA will be   (a) 4 p.u. (b) 2 p.u. (c) 1.0 p.u. (d) 0.5 p.u.

Answer : If the inertia constant H of a machine of 200 MVA is 2 p.u., its value corresponding to 400 MVA will be 1.0 p.u.

Description : A 60 Hz, 4 pole turbo generator rated 100 MVA, 13.8 KV has an inertia constant of 10 MJ/MVA. Find the stored energy in the rotor at synchronous speed.  (A) 10 MJ (B) 100 J (C) 1000 J (D) 1000 MJ

Answer : KE is equal to H X S D. 1000 MJ

Description : Why is it cheaper to transmit electrical energy at high voltage?

Answer : Because of the electrical energy was step upped by transformers the transformer have high efficiency than the electric energy is cheaper

Description : Why harmonics are generated in electrical system?

Description : Why is "RJ-45" cable called "RJ-45" ?

Answer : rj = registered jack 45 = is number of standard interface and contains 8 separate wires

Description : Why transistor is called as bipolar device.

Answer : BJT is called bipolar device because in BJT current conduction takes place due to majority as well as minority charge carriers that is because of electrons as well as holes.

Answer : Thyristor can only be turned on by small gate pulse but it cannot be turn off by using gate hence thyristor is called semi controlled device.

Answer : Thyristor can be turn on by positive gate pulse and the current will continue to flow through the device even when the gate voltage is low hence thyristor is called latching device.

Answer : Because Transformer do not have any moving part hence transformer is called static device.

Description : An electrical discharge ionizing the air around a conductor is called: w) Flux x) Corona y) Ozone z) Field

Description : An electrochemical cell which is used as a source of direct electrical current at constant voltage under standard conditions is called a : (1) Power transmittor (2) Battery (3) Uninterrupted power supply (UPS) (4) Generator

Description : Certain substances loose their electrical resistance completely at super low temperature. Such substances are called. (1) Super conductors (2) Semi conductors (3) Dielectrics (4) Perfect conductors

Description : A device which is used to limit the current in an electrical circuit is called a (1) Grid (2) Fuse (3) Hub (4) Conductor

Description : The device which converts sound energy into electrical energy is called (1) Amplifier (2) Speaker (3) Microphone (4) Transmitter

Description : effect of inductance and capacitance on performance of transmission line.

Answer : Following are the effect on performance of transmission line:  1. Due to inductance (L) voltage drop in transmission line produces.  2. Capacitor (C) draws charging current ... , transmission line efficiency, voltage regulation & also power factor of transmission line gets affected.

Description : What is inductance?

Answer : Inductance is the property of Material by which it opposes the any change of magnitude or direction of electric current passing through the conductor. The inductance is denoted by L. The unit of inductance is Henry (H).

Description : Self inductance formula

Description : Self induced voltage across an inductance

Answer : Self induced voltage across an inductance

Description : State the effects of errors in dynamometer type wattmeter due to i) pc- inductance ii) pc- capacitance iii) mutual inductance iv) Connection.

Answer : Errors in wattmeter:  i) pc - inductance: Pressure coil inductance causes wattmeter to read more power than actual .  ii) pc-capacitance: The wattmeter reads less power.  iii) ... iv) Connection: In uncompensated wattmeter , the reading of wattmeter includes the powerloss in coils.

Description : Describe with working of LCR meter for measurement of inductance.

Answer : working of LCR:- A LCR meter (Inductance (L), Capacitance (C), and Resistance (R) test equipment used to measure the inductance, capacitance and, resistance of a component. It works on the ... in parallel (as would be encountered in measuring a capacitor with a leaky dielectric) [Q setting ]

Description : Define :i) Self inductance ii) Coefficient of self induction

Answer : i) Self-inductance: It is the property by virtue of which a coil opposes change in current flowing through it by inducing an emf in it such that its effect is to circulate current (induced current) that produces a magnetic field ...          N = di/dt        N = Φ/I  It is expressed in henry.

Description : A coil of 500 turns is linked with a flux of 25 mwb, when carries a current of 12.5A. Calculate the value of self-inductance.

Answer : Ans: Self-Inductance: L = NΦ /I = 500 × 25 × 10-3 / 12.5 = 1 H

Description : In practice, a current source inverter consists of an AC/ DC converter with a large inductance ‘L’ in the output. This inductance maintains a ……… …………through the switching devices over short interval of time. A) constant current B) constant voltage C) constant power D) none of the (A), (B), (C)

Answer : In practice, a current source inverter consists of an AC/ DC converter with a large inductance ‘L’ in the output. This inductance maintains a constant current through the switching devices over short interval of time.

Description : An iron cored inductance coil can be modelled, over a normal operating range of networks ,as A) non-Linear bilateral element B) linear bilateral element C) linear time varying element D) non-linear time invariant element

Answer : An iron cored inductance coil can be modelled, over a normal operating range of networks ,as linear bilateral element

Description : These self inductance of a circuit is defined as twice the work done against the induced e.m.f. on establishing unit current in the coil. If the current to be established in the coil is doubled, the work done ... induced e.m.f. will be  1. Doubled  2. Halved  3. four times  4. Quarter times

Answer : These self inductance of a circuit is defined as twice the work done against the induced e.m.f. on establishing unit current in the coil. If the current to be established in the coil is doubled, the work done against the induced e.m.f. will be four times

Description : lt the length, number of turns and area of a coil are  doubled, the inductance of the coil

Answer : lt the length, number of turns and area of a coil are  doubled, the inductance of the coil is quadrupled

Description : A coil of inductance 240 mH and resistance 75 Ohm is connected in parallel with a capacitor across a 30 V, variable frequency supply. The current drawn by the circuit is found to be minimum when the supply frequency is 1 kHz. The ... (A) 40, 400 Hz (B) 10, 100 Hz (C) 20, 50 Hz (D) 50, 20 Hz

Answer : A coil of inductance 240 mH and resistance 75 Ohm is connected in parallel with a capacitor across a 30 V, variable frequency supply. The current drawn by the circuit is found to be minimum ... supply frequency is 1 kHz. The approximate values of Q-factor and bandwidth are, respectively 20, 50 Hz

Description : A network consists of several inductances connected in parallel. The equivalent inductance of the network is given by (A) the sum of the individual inductances. (B) the reciprocal of the ... of individual inductances. (D) the reciprocal of the sum of reciprocals of individual inductances.

Answer : A network consists of several inductances connected in parallel. The equivalent inductance of the network is given by the reciprocal of the sum of reciprocals of individual inductances.

Description : What is the value of Inductance of a coil that induces 20 V when the current through the coil changes from 12 to 20 A in 2 seconds? A. 2 H B. 3 H C. 4 H D. 5 H

Answer : 5 H is the value of Inductance of a coil that induces 20 V when the current through the coil changes from 12 to 20 A in 2 seconds.

Description : A 220 kV, 3 phase transmission line is 60 km long. The resistance is 0.15 ohm / km and the inductance is 1.4 mH / km. Use the short line model to find the power at the sending end when the line is supplying a three ... at 0.8 pf lagging at 220 kV.  (A) 5.58MW (B) 80MW (C) 85.58MW (D) 74.42 MW

Description : A parallel combination of capacitance C and resistance R is connected in series with inductance L and small resistance r. Under what condition will the circuit be non-reactive?  (A) C=LR (B) C=LR2 (C) C=L/R2 (D) C=L/R

Description : The current i(t), through a 10 Ω resistor in series with an inductance, is given by I(t) = 3 + 4sin (100t + 450 ) + 4 sin(300t +600) amperes. The RMS values of the current and power dissipation ... respectively (B) √35 A, 350 W respectively (C) 5 A, 250 W respectively (D) 11 A, 1210 W respectively

Description : A three phase 50 Hz, 400 kV transmission line is 300 km long. The line inductance is 0.97 mH/km per phase and capacitance is 0.0115 mF/km per phase. Assume a loss less line. Determine the line wavelength (a line phase constant).  (A) 1250 km (B) 6578 km (C) 4990 km (D) 2445 km

Description : A choke coil having resistance RΩ and of inductance L Henry is shunted by a capacitor of C farads. The dynamic impedance of the resonant circuit would be:  (A) R/LC (B) C/RL (C) L/RC (D) 1/RLC

Description : The differential coupling of two coils in series connection has self-inductance of 2 mH & 4 mH & a mutual inductance of 0.15 mH. The equivalent inductance of the combination is:  (A) 5.7 mH (B) 5.85 mH (C) 6 mH (D) 6.15 mH

Answer : An undesirable side effect of motional inductance of large conduction specimens is eddy currents.

Description : A series RLC circuit has a resistance of 50 , inductance of 0.4H and a capacitor of 10µF. The circuit is connected across a 100V supply. The resonance frequency and the current through the resistance are

Answer : A series RLC circuit has a resistance of 50 , inductance of 0.4H and a capacitor of 10µF. The circuit is connected across a 100V supply. The resonance frequency and the current through the resistance are 500 rad/s and 2A.

Description : Two similar coils have self inductance of 1 mH each. Coefficient of coupling is 0.5. The mutual inductance M is

Answer : Two similar coils have self inductance of 1 mH each. Coefficient of coupling is 0.5. The mutual inductance M is 0.5 mH.

Answer : Inductance coils are basically designed for High Q.

Description : The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is_______Vs.

Answer : The initial rate of rise of current through a coil of inductance 10 H when suddenly connected to a D.C. supply of 200 V is 20 Vs

Description : When both the inductance and resistance of a coil are doubled the value of?

Answer : When both the inductance and resistance of a coil are doubled the value of time constant remains unchanged.

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