# A capacitor opposes:

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A capacitor opposes:

A capacitor opposes: change in voltage

## Related questions

A capacitor used for power factor correction in single phase circuit decreases: (1) Power factor (2) Line current (3) Both line current and p.f. (4) The line current and increases p.f.

The reactance offered by a capacitor to an alternating current of frequency 50 Hz is 10 ohm. If frequency is increased to 100 Hz, the reactance will be (a) 2.5 ohm (b) 5.0 ohm (c) 20.0 ohm (d) 40.0 ohm

In a parallel plate capacitor of capacitance Co, the electric field is E. If a dielectric slab with dielectric constant = 7 is introduced to fill capacitor completely, the electric field will become (a) 7E (b) E/7 (c) E/3.5 (d) E. Co

If the output filter capacitor in a power supply actually had a value twice its stated value, which of the following symptoms would be found?   a. The output voltage would be doubled and a small improvement in the ripple voltage would be detected.  b. The ripple voltage would be half of what is expected and a ... output voltage would be detected.  c. The output and ripple voltage would be greater than expected.  d. The output and ripple voltage would be less than expected.

For a parallel plate capacitor which is being charged out of the following the incorrect statement is   (A) Energy stored in the capacitor does not enter it through the connecting wire through the space around the wires and plates of capacitor.   (B) Rate at which energy flows into this volume is equal ... poynting vector points everywhere radially outward of the volume between plates.   (D) The poynting vector points everywhere radially in to the volume between the plates.

A capacitor of capacitance 50 micro farads is charged to a potential difference of 200 Volts. Find out energy stored in the condenser?

The capacitance of the capacitor is directly proportional to the

The property of a material which opposes the creation of magnetic flux in it is known as?

Which law states that induced e.m.f and current always opposes the cause producing them?

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Equivalent capacitance ‘C’ of a system of capacitors C1,C2,C3 connected in parallel is

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Define dielectric strength for a capacitor.

A certain common-emitter amplifier has a voltage gain of 100. If the emitter bypass capacitor is removed.  a. The circuit will become unstable b. The voltage gain will decrease  c. The voltage gain will increase d. The circuit will become stable

What happens to current flow in a capacitive circuit when the DC voltage across the capacitor is approximately equal to the source voltage?

As compared to a split phase motor, a capacitor start motor has _____.

The capacitance of a capacitor is not affected by (a) Plate area (b) Plate separation (c) Nature of dielectric (d) Plate thickness

If a capacitance is charged by a square wave current source, then the voltage across the capacitor will be (a) Square wave (b) Step function (c) Triangular wave (d) Zero

If the voltage applied across a capacitor is triangular in waveform, the waveform of the current is (a) Triangular (b) Rectangular (c) Sinusoidal (d) Trapezoidal

At an industrial sub-station with a 4 MW load, a capacitor of 2 MVAR is installed to maintain the load power factor at 0.97 lagging. If the capacitor goes out of service, the load power factor becomes (A) 0.85 (B) 1.00 (C) 0.80 lag (D) 0.90 lag

In a series RLC circuit at resonance, the magnitude of the voltage developed across the capacitor  A) Is always zero B) Can never be greater than the input voltage C) Can be greater than the input voltage, however, it is 90° out of phase with the input voltage D) Can be greater than the input voltage, and is in phase with the input voltage

A stand alone engine driven synchronous generator is feeding a partly inductive load. A capacitor is now connected across the load to completely nullify the inductive current. For this operating condition.  (A) the field current and fuel input have to be reduced (B) the field current and fuel input have to be increased (C) the field current has to be increased and fuel input left unaltered (D) the field current has to be reduced and fuel input left unaltered

For a single phase capacitor start induction motor, which of the following statements is valid?  A) The capacitor is used for power factor improvement B) The direction of rotation can be changed by reversing the main winding terminals C) The direction of rotation cannot be changed D) The direction of rotation can be changed by interchanging the supply terminals

A single phase CSI has capacitor C as the load. For a constant source current, the voltage across the capacitor is   (A) square wave (B) triangular wave (C) step function (D) pulsed wave

A capacitor and coil in parallel is called

The purpose of connecting a capacitor in fluorescent tube circuit is • To increase switching on time • To decrease switching off time • To increase power factor • To decrease power consumption

The synchronous motor can be used as a capacitor • By increasing excitation • By decreasing excitation • By increasing speed • By decreasing speed

Plate separation of a parallel plate air capacitor is reduced keeping the voltage constant. The energy stored in the capacitor shall • Increase • Decrease • Remain constant • Remain zero

When an alternating potential is applied to a capacitor, the current in the circuit will  1. lead the applied potential 2. lag the applied potential 3. be in phase with the applied potential 4. none

For a DC circuit capacitor is

An inductor of Q factor 10 is connected in series with a capacitor having a Q factor of 100. The overall Q factor of the circuit is :  (A) 100/11 (B) 11/100 (C) 110 (D) 1000

What is a capacitor voltage transformer? A) It is a transformer used in power systems to step up low voltage signals and provide extra high voltage B) It is a transformer used in power systems to step up high voltage signals and provide extra high voltage C) It is a transformer used in power systems to step down extra high voltage signals and provide low voltage D) None of these

What is the charge on each capacitor when a 150 V is applied across two capacitors with values 5 μF and 10 μF, connected in series? A) 500 μC B) 0.5 μC C) 0.5 C D) None of these

What is the stored energy when 200 V is applied across a 7 μF capacitor? A) 1400 Joules B) 0.7 Joules C) 0.14 Joules D) None of these

What is the capacitance when a capacitor passes a current of 31.43 mA when supplied with 40 V AC with a frequency of 1000 Hz? A) 0.125 F B) 0.125 μF C) 1257.2 μF D) None of these

Which of the following can be used to measure the capacitance of a capacitor? A) Rheostat B) Schering bridge C) Wheatstone bridge D) None of these

Dielectric loss in a capacitor is best measured by (A) Wien Bridge (B) Schering Bridge (C) Anderson Bridge (D) Heaviside-Campbell Equal Ratio Bridge

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 approximate values of Q-factor and bandwidth are, respectively (A) 40, 400 Hz (B) 10, 100 Hz (C) 20, 50 Hz (D) 50, 20 Hz

A 100 pF capacitor has a maximum charging current of 150 μA.What is the slew rate ? (A) 1.5 V/μs (B) 1.05 V/μs (C) 0.15mV/s (D) 10.5 mV/s

A synchronous capacitor is (A) an unloaded and under excited 3-phase synchronous motor (B) a loaded and over excited 3-phase synchronous generator (C) an unloaded and over excited 3-phase synchronous motor (D) a 3-phase synchronous generator loaded with a capacitor bank

With the help of which bridge are the capacitance and dielectric loss of a capacitor generally measured ?

Reduction in the value of capacitance of a capacitor -start motor, results in reduced: (A) noise (B) speed (C) starting torque (D) armature reaction

Ratings on a capacitor are given 25 µF, 12 V. Also a plus sign is written near one of its terminals. The capacitor is: -  a) Mica capacitor b) Ceramic capacitor c) Electrolytic capacitor d) Paper capacitor