# MCQs on RC Time Constant in Electronic Circuit ## RC and L/R Time Constant – Definition

In the case of RC time constant, we will define that a fixed or constant time period a capacitor takes to charge 63.2 percent voltage. But the complete charging upto 100% will be complete after 5 time constant. In the case of L/R time constant, we can simply understand that an inductor takes 1 L/R time constant to complete the current change upto 63.2%. The only difference between RC v.s R/L time constant is just a concept of current and voltage.

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The aim to provide MCQs on RC time constant in electronic circuit objective questions and answers to understand the formula and calculation of time constant. If you are willing to learn the concepts of Basic Electronics MCQs multiple choice questions with answer then read all the multiple choice questions and answers completely. You will be surely qualify for all kinds of Quiz / tests / Interviews after understanding the principle of RC and R/L Time Constant. If you are a students, technician or teacher then you can learn the basic concept of time constant in electronic circuit principle, function and applications.

### RC Time Constant in Electronic Circuit (Objective Questions)

Q1. The time constant is the time required to change upto ________ percent voltage through capacitor and current through inductor.                                .

1. 62.3
2. 63.2
3. 64.3
4. 63.4

Q2. The transient response is measured in the term of L/R ratio.         True / False

Q3. The formula used to calculate the time constant in inductive circuit is ___________.

1. RC
2. L/R
3. R/C
4. LC/R

Q4. When an inductive Cct is opened, the time constant for current becomes very short.                     True / False

Q5. The energy stored in the magnetic field is______________________.

1. E = 64 × 10-4  J
2. E = 1/2 LCR
3. E = 1/2 LI2
4. a & c are correct

Q6. When the voltage across the capacitor and current across the inductor becomes equal to the source current or voltage is five time constant .            True / False

Q7. The current in inductor reached to the 63.2% within 0.1 sec then the current rises to 100% within _________ sec.

1. 0.2
2. 0.3
3. 0.4
4. 0.5

Q8. In the inductive circuit, the current reaches to the 63.2% in 1 L/R time constant and becomes 100% within 5 L/R time constant.            True / False

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Q9. The RC time constant becomes __________ with larger value of R & C.

1. shorter
2. longer
3. a & b are correct
4. all are correct

Q10. The high value of self induced voltage across inductor produces when RL circuit is opened.         True / False

Q11. When RL circuit is opened, the produce self-induce voltage which is ________ than the applied voltage.

1. short
2. greater
3. infinity
4. same

Q12. The neon bulb requires 90 voltages for the ionization function.                                   True / False

Q13. The formula to calculate the time constant in capacitive circuit is _____________.

1. RC
2. RC/L
3. R/C
4. R/L × C

Q14. The energy stored in a capacitor formula is E = 1/2 CV2               True / False

Q15. The long or short time constant RC time constant depends on the ____________ of applied voltage.

1. current
2. frequency
3. pulse width
4. voltage

Q16. A short RC time constant is equal to the one-fifth pulse width of the applied voltage.                         True / False

Q17. A ________ RC time constant is equal to the 5 times longer pulse width of applied voltage.

1. Long
2. Short

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Q18. The voltage across R in a RC circuit is called differentiated output.                   True / False

Q19. The voltage across C in an RC circuit is called ______________ circuit.

1. integrated
2. differentiated

Q20. A short & medium time constant is generally used for differentiated circuit.                 True / False

Answer:    False (Only Short)

Q21. A _____________ time constant is generally used for integrated circuit.

1. long
2. short
3. medium
4. b & c are correct

Q22. Generally, the time constant is made much shorter or longer than a factor of 5 to get better wave shapes.                                                                                                                                                                                  True / False

Q23. The factor of 0.5 time constant is equal to the amplitude of ______________.

1. 20%
2. 50%
3. 63%
4. 40%

Q24. The factor of 4-time constant is equal to the amplitude of 98%.                             True / False

Q25. The amplitude of 86% is equal to the time constant of _____________.

1. 3
2. 4
3. 5
4. 2

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Q26. The method of time constant is used for L & C to analysis the non-sinusoidal wave-forms.               True / False