Free Alternating Current MCQs with Answers
592 Alternating Current MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Alternating current varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
Last updated
Read the Alternating Current notesFree MDCAT chapter notes with key terms592 questions · page 30 of 30
- A. Gamma rays, ultraviolet rays, radio waves
- B. Gamma rays, visible radiation, ultraviolet rays
- C. Microwaves, ultraviolet rays, X-rays
- D. Radio waves, visible radiation, infrared radiation
Explanation: The electromagnetic spectrum is as such as wavelength decreases frequency increases, therefore the correct answer would be C ,as the…
Correct answer: Microwaves, ultraviolet rays, X-rays- A. Speed
- B. Energy
- C. Frequency
- D. Wavelength
Explanation: All electromagnetic radiations such as microwave, gamma rays or radio waves travel with a speed of light in a vacuum which is equal to 3.0…
Correct answer: Speed- A. An electric field
- B. Magnetic field
- C. Both A and B
- D. None of the above
Explanation: Faraday's law of electromagnetic induction states that a changing electric flux will result in the induction of a magnetic field.
Correct answer: Both A and B- A. Sound
- B. Supersonic
- C. Ultrasonic
- D. Light
Explanation: The correct answer is that the signal from a remote control travels at the speed of light.
Correct answer: Light- A. X-rays
- B. Gamma rays
- C. Microwaves
- D. Ultraviolet rays
Explanation: Gamma rays have the smallest wavelength of all electromagnetic waves, making them the highest in energy.
Correct answer: Gamma rays- A. An electric field only
- B. A magnetic field only
- C. Electromagnetic radiation only
- D. All of the above
Explanation: Accelerating charges produce changing electric and magnetic fields. Changing electric fields produce magnetic fields and changing magnetic…
Correct answer: All of the above- A. Maximum
- B. Zero
- C. Maximum and minimum
- D. No change in emf
Explanation: Zero: The mean value of a sinusoidal emf over a cycle is zero. This is because the positive and negative values of the sinusoidal wave…
Correct answer: Zero- A. Zero
- B. Constant
- C. Positive
- D. Maximum
Explanation: The average current value in a complete cycle of AC waveform, such as a sine wave, is zero because the positive and negative parts of the…
Correct answer: Zero- A. 100 A
- B. 25 A
- C. 50 A
- D. 20 A
Explanation: The sinusoidal AC current given by the equation I = 50 sin(20t) has a peak value that is determined by the amplitude of the sine function.
Correct answer: 50 A- A. 100 Hz
- B. 200Hz
- C. 50 Hz
- D. 150Hz
Explanation: If we compare the given equation with the formula V=Vosin(wt+ϕ),Vo=20, ϕ=0, w=100.
Correct answer: 50 Hz- A. 5A
- B. 2.5A
- C. 5√2 A
- D. 52 A
Explanation: The mean square value (RMS value) of the current is calculated as:RMS value = Peak value / √2= 5√2 / √2= 5 A Therefore, option a is correct.
Correct answer: 5A- A. 150Hz
- B. 50Hz
- C. 100Hz
- D. 200Hz
Explanation: In most countries, the domestic electricity supply, also known as the mains electricity or grid power, has a frequency of 50Hz (50 cycles…
Correct answer: 50Hz