If the frequency of an AC source is doubled, the impedance of a pure resistor ____________.
remains unchanged
To determine the effect of changing the frequency of an AC source on the impedance of a pure resistor, we need to understand some basic electrical concepts:
- Impedance of a Resistor: In an AC circuit, the impedance \(Z\) of a pure resistor is given by its resistance \(R\). This is because a resistor does not have any reactive components (inductance or capacitance) that would cause its impedance to depend on frequency. Therefore, impedance \(Z\) of a pure resistor is simply \(Z = R\).
- Effect of Frequency: The impedance of a resistor is independent of the frequency of the AC supply. This means that changing the frequency of the AC source will not affect the impedance of a pure resistor. The impedance remains constant regardless of frequency changes.
Based on these principles, when the frequency of an AC source is doubled, the impedance of a pure resistor remains unchanged.
Therefore, the correct answer is: remains unchanged.
Let's evaluate the options:
- Remains unchanged: Correct - As explained, because resistive impedance is independent of frequency.
- Quadruples: Incorrect - Impedance of a pure resistor is not influenced by frequency, so it does not quadruple.
- Doubles: Incorrect - Similar reasoning to quadruples; impedance remains the same.
- Halves: Incorrect - The impedance cannot halve as the frequency increases; it remains unchanged.
Similar Questions
Consider the following statements about torque in synchronous motors.
I. The torque in a synchronous motor is produced only when the rotor is locked into synchronism.
II. The torque is directly proportional to the sine of the load angle (δ).
III. Synchronous motor develops starting torque proportional to the power input.
IV. Maximum torque occurs at δ = 180°.
Which of the above statements are correct?
Which of the following is a key maintenance practice for reliable operation of a 3-phase induction motor?
Which of the following sets of statements about the causes of errors in current transformers is correct?
i) Leakage reactance in secondary winding contributes to ratio error
ii) High magnetizing current increases phase angle error
iii) Burden with low power factor increases phase angle error
iv) Core saturation reduces both ratio and phase angle errors
A single-phase preventer continuously monitors and protects preferably which motor against phase failure?
Important Questions from Three Phase Induction Motor
The stator of a 3-phase induction motor has 4 slots per pole phase. If the supply frequency is 50 Hz, calculate the number of stator poles produced and the total number of slots on the stator, respectively.
Which of the following is NOT a valid advantage of skewing in squirrel cage induction motor?
In an induction motor for a value slip(s) = 0, the torque (T) is
When an induction machine is allowed to run above synchronous speed, then this characteristic exactly matches which of the following options?
A 3-phase. 6-pole, 50 Hz, squirrel cage induction motor is running at a slip of 5%. The speed of stator magnetic field to rotor magnetic field and speed of rotor with respect to stator magnetic field are
