This quiz works best with JavaScript enabled. Home > Class 12 > Class 12 Physics (Part I) Chapter 7 Alternating Current – Quiz 29 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 29 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What is the formula for calculation capacitive reactance? A) $X_C=\frac{1}{2\pi fC}$. B) $X_C=2\pi fC$. C) $X_L=2\pi fL$. D) None of the above. Show Answer Correct Answer: A) $X_C=\frac{1}{2\pi fC}$. 2. The variation of a quantity such as voltage or current shown on a graph is known as ..... A) Waveform. B) Peak value. C) Instantaneous value. D) Period. Show Answer Correct Answer: A) Waveform. 3. In radio Circuit, a capacitor of 2microfarad is used, if the frequency is 1000Hz and current flowing in it is 1mA, then Calculate the Voltage across the capacitor A) 29.57mV. B) 39.57mV. C) 59.57mV. D) 79.57mV. Show Answer Correct Answer: D) 79.57mV. 4. RMS value of AC is numerically: A) Equal to peak value. B) Less than peak value. C) Greater than peak value. D) Independent of peak value. Show Answer Correct Answer: B) Less than peak value. 5. The period of a wave is A) The same as frequency. B) Time required to complete one cycle. C) Expressed in amperes. D) None of the above. Show Answer Correct Answer: B) Time required to complete one cycle. 6. The power factor can be defined as the ratio of true power to ..... A) Apparent power. B) Total resistance. C) Total current. D) Reactive power. Show Answer Correct Answer: A) Apparent power. 7. What happens to the current at resonance in an L-C circuit? A) It is minimum. B) It is maximum. C) It is constant. D) It is zero. Show Answer Correct Answer: B) It is maximum. 8. If frequency of rotating coil of an A.C. generator is f Hz then frequency of e.m.f. produced in Pakistan is: A) 50 Hz. B) 60 Hz. C) F Hz. D) None of these. Show Answer Correct Answer: C) F Hz. 9. What is the main source of alternating current for homes? A) Power plants. B) Solar cells. C) Fuel cells. D) Batteries. Show Answer Correct Answer: A) Power plants. 10. A wire carries an alternating current of peak value 3 A. Which of the following is the root-mean-square value of this current? A) 1.5 A. B) 2.1 A. C) 4.2 A. D) 9.0 A. Show Answer Correct Answer: B) 2.1 A. 11. Which of the following is NOT a component of a simple single-phase AC generator? A) Stator. B) Rotor. C) Transformer. D) Slip rings. Show Answer Correct Answer: C) Transformer. 12. If the circuit is at resonance the impedance becomes A) Maximum. B) Minimum. C) Ohmic resistance. D) Capacitive or inductive reactance. Show Answer Correct Answer: C) Ohmic resistance. 13. A transformer steps up 220 V to 2200 V. What is the transformation ratio? A) 20. B) 0.1. C) 0.2. D) 10. Show Answer Correct Answer: D) 10. 14. The following statement describe about an capacitance except ..... A) Ability to store charge for a given amount of voltage supply. B) Represented by C. C) Standard unit is Farad. D) Voltage is always leading current. Show Answer Correct Answer: D) Voltage is always leading current. 15. The number of cycles a waveform completes per second determines the ..... A) Voltage. B) Frequency. C) Resistance. D) Amperage. Show Answer Correct Answer: B) Frequency. 16. When a conductor cuts the magnetic flux lines at?, the maximum voltage will be induced into the conductor. A) 60 deg. B) 90 deg. C) 180 deg. D) 360 deg. Show Answer Correct Answer: B) 90 deg. 17. Which component is commonly found in AC circuits to store electrical energy? A) Resistor. B) Capacitor. C) Diode. D) Transistor. Show Answer Correct Answer: B) Capacitor. 18. What is one-half of an AC cycle? A) Alternation. B) Altercation. C) Don't know because I did not study this. D) None of the above. Show Answer Correct Answer: A) Alternation. 19. Capacitors are sometimes used in DC circuits to A) Counteract inductive reactance at specific locations. B) Smooth out slight pulsations in current/voltage. C) Assist in stepping voltage and current up and/or down. D) None of the above. Show Answer Correct Answer: B) Smooth out slight pulsations in current/voltage. 20. A student is asked to explain why transformers are used in AC power transmission but not in DC transmission. What is the correct explanation? A) Transformers work only with DC because DC changes direction. B) Transformers require alternating current to operate, as they rely on changing magnetic fields. C) Transformers can operate with both AC and DC. D) Transformers are used to store energy. Show Answer Correct Answer: B) Transformers require alternating current to operate, as they rely on changing magnetic fields. 21. Which of the following instrument may be used to measure AC A) Voltmeter. B) Moving coil galvanometer. C) Hot wire meters. D) Ballistic galvanometer. Show Answer Correct Answer: C) Hot wire meters. 22. A device that uses electromagnetic induction to transfer electrical energy from one circuit to another is a(n) ..... A) Coil. B) Inductor. C) Transformer. D) Capacitor. Show Answer Correct Answer: C) Transformer. 23. Fill in the blank:Hair growth will take longer to ..... A) Re-grow. B) Fall. C) Change. D) Stop. Show Answer Correct Answer: A) Re-grow. 24. The voltage of domestic AC is 220 V. What does this represent? A) Mean voltage. B) Peak voltage. C) Root mean voltage. D) Root mean square voltage. Show Answer Correct Answer: D) Root mean square voltage. 25. How can phase difference be represented graphically? A) Phase difference can be represented graphically by plotting waveforms and observing the horizontal shift between them. B) Through the frequency of the waves. C) By calculating the wavelength of the waves. D) By measuring the amplitude of the waves. Show Answer Correct Answer: A) Phase difference can be represented graphically by plotting waveforms and observing the horizontal shift between them. ← PreviousNext →Related QuizzesClass 12 Physics (Part I) Chapter 7 Alternating Current Quiz 1Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 2Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 3Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 4Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 5Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 6Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 7Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 8Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 9Class 12 Physics (Part I) Chapter 7 Alternating Current Quiz 10 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books