MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
When the coil is wrapped around a ferromagnetic core, why is it difficult to determine the inductance? |
| A. | The variation of flux is no longer proportional to the variation of current |
| B. | Current does not exist in the coil |
| C. | Flux does not exist in the coil |
| D. | The value of current is too large to measure |
| Answer» B. Current does not exist in the coil | |
| 2. |
Calculate the number of turns in an inductor with a ferromagnetic core when the inductance is 4000 H, the current changes from 5A to 7A and the flux changes from 760 to 800 Wb. |
| A. | 100 |
| B. | 200 |
| C. | 300 |
| D. | 400 |
| Answer» C. 300 | |
| 3. |
The flux linkage in coil 1 is 3 Wb and it has 500 turns and the current in coil 2 is xA, calculate the value of x if the mutual inductance is 750H. |
| A. | 1A |
| B. | 2A |
| C. | 3A |
| D. | 4A |
| Answer» C. 3A | |
| 4. |
Among the following, which is the right formula for inductance? |
| A. | L=emf*t/I |
| B. | L=emf/t*I |
| C. | L=emf*I/t |
| D. | L=emf*t*I |
| Answer» B. L=emf/t*I | |
| 5. |
When a ferromagnetic core is inserted into an inductor, what happens to the flux linkage? |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | Becomes zero |
| Answer» B. Decreases | |
| 6. |
What happens to the current when a ferromagnetic material is introduced within an inductor? |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | Becomes zero |
| Answer» D. Becomes zero | |
| 7. |
If the current changes from 20A to 10A in 5 seconds and the value of inductance is 1H, calculate the emf induced. |
| A. | 8V |
| B. | 6V |
| C. | 4V |
| D. | 2V |
| Answer» E. | |
| 8. |
What happens to the inductance as the area of the cross section of the coil increases? |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | Becomes zero |
| Answer» B. Decreases | |
| 9. |
Find voltage across 2H inductor. |
| A. | 2V |
| B. | 10V |
| C. | 12V |
| D. | 20V |
| Answer» B. 10V | |
| 10. |
If the power factor is 1/10 and the value of impedance is 20 ohm, calculate the resistance in the circuit. |
| A. | 1 ohm |
| B. | 2 ohm |
| C. | 3 ohm |
| D. | 4 ohm |
| Answer» C. 3 ohm | |
| 11. |
What happens to the coupling coefficient when the flux linkage of coil 1 and coil 2 increases? |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | Becomes zero |
| Answer» B. Decreases | |
| 12. |
Among the following, which is the right formula for decay in an inductive circuit? |
| A. | i=I(1-e⁻ᵗ/time constant) |
| B. | i=I(1-eᵗ /time constant) |
| C. | i=(1-e⁻ᵗ /time constant) |
| D. | i=I(e⁻ᵗ /time constant) |
| Answer» E. | |
| 13. |
What is the coupling coefficient when all the flux of coil 1 links with coil 2? |
| A. | 0 |
| B. | 100 |
| C. | 1 |
| D. | Insufficient information provided |
| Answer» D. Insufficient information provided | |
| 14. |
What is the coupling coefficient when there is ideal coupling? |
| A. | 0 |
| B. | 100 |
| C. | 1 |
| D. | Insufficient information provided |
| Answer» D. Insufficient information provided | |
| 15. |
Among the following, which is the right formula for inductance of N turns? |
| A. | L=et/Ni |
| B. | L=N*i *e*t |
| C. | L=Ni/et |
| D. | L=N/iet |
| Answer» B. L=N*i *e*t | |
| 16. |
The flux linkage in coil 1 is 3Wb and it has x turns and the current in coil 2 is 2A, calculate the value of x if the mutual inductance is 750H. |
| A. | 300 |
| B. | 400 |
| C. | 500 |
| D. | 700 |
| Answer» D. 700 | |
| 17. |
The phenomenon due to which there is an induced current in one coil due to the current in a neighbouring coil is? |
| A. | Electromagnetism |
| B. | Susceptance |
| C. | Mutual inductance |
| D. | Steady current |
| Answer» D. Steady current | |
| 18. |
At steady state, the current in the inductor is? |
| A. | Maximum |
| B. | Minimum |
| C. | Zero |
| D. | Infinity |
| Answer» B. Minimum | |
| 19. |
An RL network is one which consists of ____________ |
| A. | Resistor and capacitor in parallel |
| B. | Resistor and capacitor in series |
| C. | Resistor and inductor in parallel |
| D. | Resistor and inductor in series |
| Answer» E. | |
| 20. |
If tan ϕ = 10 and the resistance is 2 ohm, calculate the inductive reactance. |
| A. | 10 ohm |
| B. | 20 ohm |
| C. | 30 ohm |
| D. | 40 ohm |
| Answer» C. 30 ohm | |
| 21. |
As the number of turns in the coil increases, what happens to the inductance of the coil? |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | Becomes zero |
| Answer» B. Decreases | |
| 22. |
Can the coupling coefficient practically ever be equal to 1? |
| A. | Yes |
| B. | No |
| C. | Depends on the current in coil 1 |
| D. | Depends on the current in coil 2 |
| Answer» C. Depends on the current in coil 1 | |
| 23. |
What is the power in the magnetic field if the current in a coil has a constant inductance of L henrys grows at a uniform rate? |
| A. | LI/2t |
| B. | LI²/2t |
| C. | L/2It |
| D. | L/2I²t |
| Answer» C. L/2It | |
| 24. |
What happens to the inductance as the length of the magnetic circuit increases? |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | Becomes zero |
| Answer» C. Remains the same | |
| 25. |
The unit for inductance is ___________ |
| A. | Ohm |
| B. | Henry |
| C. | A/m |
| D. | A/s |
| Answer» C. A/m | |
| 26. |
A coil has a resistance of 4 ohms and an inductance of 2H. It is connected to a 20V dc supply. Calculate the initial value of the current in the circuit. |
| A. | 5A |
| B. | 10A |
| C. | 0 A |
| D. | 20A |
| Answer» D. 20A | |
| 27. |
A coil has a resistance of 4 ohms and an inductance of 2H. It is connected to a 20V dc supply. Calculate the final value of the current in the circuit. |
| A. | 5A |
| B. | 10A |
| C. | 15A |
| D. | 20A |
| Answer» B. 10A | |
| 28. |
Initially, when the switch in a series RL circuit is closed, the current in the inductor is? |
| A. | Maximum |
| B. | Minimum |
| C. | Zero |
| D. | Infinity |
| Answer» D. Infinity | |
| 29. |
What happens to the inductance when the magnetic field strength decreases? |
| A. | Increases |
| B. | Decreases |
| C. | Remains the same |
| D. | Becomes zero |
| Answer» C. Remains the same | |
| 30. |
A laminated steel ring is wound with 200 turns. When the magnetizing current varies between 5 and 7 A, the magnetic flux varies between 760 and 800 Wb. Calculate the inductance of the coil. |
| A. | 40H |
| B. | 4 H |
| C. | 4000H |
| D. | 0.004 H |
| Answer» D. 0.004 H | |
| 31. |
Practical application of mutual inductance is ____________ |
| A. | DC generator |
| B. | AC generator |
| C. | Transformer |
| D. | Capacitor |
| Answer» D. Capacitor | |
| 32. |
What is the unit for inductive reactance? |
| A. | Henry |
| B. | Ohm |
| C. | Farad |
| D. | Volts |
| Answer» C. Farad | |
| 33. |
What is the expression for current in the given circuit? |
| A. | i=2(e⁻²ᵗ)A |
| B. | i=2(1-e⁻²ᵗ)A |
| C. | i=2(e²ᵗ)A |
| D. | i=2(1+e⁻²ᵗ)A |
| Answer» C. i=2(e²ᵗ)A | |
| 34. |
If the current changes from 5A to 3A in 2 seconds and the inductance is 10H, calculate the emf. |
| A. | 5V |
| B. | 10V |
| C. | 15V |
| D. | 20V |
| Answer» C. 15V | |
| 35. |
When inductors are connected in series, the voltage across each inductor is _________ |
| A. | Equal |
| B. | Different |
| C. | Zero |
| D. | Infinity |
| Answer» C. Zero | |
| 36. |
In a series circuit, which of the parameters remain constant across all circuit elements such as resistor, capacitor, inductor etc? |
| A. | Voltage |
| B. | Current |
| C. | Both voltage and current |
| D. | Neither voltage nor current |
| Answer» C. Both voltage and current | |
| 37. |
Three inductors having inductance values 3H, 4H and 5H are connected in series, calculate the equivalent inductance. |
| A. | 10H |
| B. | 12H |
| C. | 3H |
| D. | 5H |
| Answer» C. 3H | |
| 38. |
When inductances are connected in series, the equivalent inductance is ____________ the largest individual inductance. |
| A. | Greater than |
| B. | Less than |
| C. | Equal to |
| D. | Not related to |
| Answer» B. Less than | |
| 39. |
What is the equivalent inductance when inductors are connected in series? |
| A. | Sum of all the individual inductances |
| B. | Product of all the individual inductances |
| C. | Sum of the reciprocal of all the individual inductances |
| D. | Product of the reciprocal of all the individual inductances |
| Answer» B. Product of all the individual inductances | |
| 40. |
The charging time constant of a circuit consisting of an inductor is the time taken for the voltage in the inductor to become __________ % of the initial voltage. |
| A. | 33 |
| B. | 63 |
| C. | 37 |
| D. | 36 |
| Answer» D. 36 | |
| 41. |
Calculate the final flux in an inductor having inductance 4000 H, number of turns is 200 and the current changes from 5A to 7A. The initial flux is 760 Wb. |
| A. | 200 Wb |
| B. | 400 Wb |
| C. | 600 Wb |
| D. | 800 Wb |
| Answer» E. | |
| 42. |
In a pure inductive circuit, the power factor is? |
| A. | Maximum |
| B. | Minimum |
| C. | 0 |
| D. | Infinity |
| Answer» D. Infinity | |
| 43. |
Calculate the initial current in an inductor having inductance 4000 H, number of turns is 200 and the flux changes from 760 to 800 Wb. Current changes to 7A. |
| A. | 10A |
| B. | 2A |
| C. | 3A |
| D. | 5A |
| Answer» E. | |
| 44. |
Calculate the change in flux of an inductor having inductance 4000 H, number of turns is 200 and the current changes from 5A to 7A. |
| A. | 20 Wb |
| B. | 40 Wb |
| C. | 60 Wb |
| D. | 80 Wb |
| Answer» C. 60 Wb | |
| 45. |
Among the following, which is the right formula for growth in an inductive circuit? |
| A. | a |
| B. | b |
| C. | c |
| D. | d |
| Answer» E. | |
| 46. |
What is Helmholtz equation? |
| A. | a |
| B. | b |
| C. | c |
| D. | d |
| Answer» C. c | |
| 47. |
What is the voltage across the inductor at t=0? |
| A. | 0V |
| B. | 20V |
| C. | 60V |
| D. | 58V |
| Answer» D. 58V | |
| 48. |
If the switch is opened at t=0, what is the current in the circuit? |
| A. | 0A |
| B. | 1A |
| C. | 2A |
| D. | 3A |
| Answer» D. 3A | |
| 49. |
If the switch is closed at t=0, what is the current in the circuit? |
| A. | 0A |
| B. | 10A |
| C. | 20A |
| D. | 30A |
| Answer» B. 10A | |
| 50. |
WHAT_IS_THE_UNIT_FOR_INDUCTIVE_REACTANCE??$ |
| A. | Henry |
| B. | Ohm |
| C. | Farad |
| D. | Volts |
| Answer» C. Farad | |