| 1 |
When the back emf is zero, its draws. |
- A. Zero current
- B. Minimum current
- C. Maximum current
- D. Steady current
|
| 2 |
A step up transformer is used 120 V line to provide 240 V. If primary coil has 100 turns the number of turns is secondary is. |
- A. 50
- B. 100
- C. 150
- D. 200
|
| 3 |
The Si unit of Mutual inductance is: |
- A. VA<sup>-1</sup>S<sup>-1</sup>
- B. VAS<sup>-1</sup>
- C. VSA<sup>-1</sup>
- D. ASV<sup>-1</sup>
|
| 4 |
The unit of induced emf is |
- A. Ampere
- B. Volt
- C. Joule/coulomb
- D. Both (b) and (c)
|
| 5 |
The magnitude of motional emf is given by |
|
| 6 |
When the back emf in a current is zero, it draws |
- A. Zero current
- B. Maximum current
- C. Minimum current
- D. Steady average current
|
| 7 |
Energy density of an inductor is: |
- A. UM=1/2μ<sub>∘</sub>/B<sup>2</sup>
- B. Um = 2μ<sub>∘</sub>/B
- C. UM = 1/2B<sup>2</sup>/μ<sub>∘</sub>
- D. Um = 2B<sup>2</sup>/μ<sub>∘</sub>
|
| 8 |
If magnetic field is doubled then magnetic energy density becomes. |
- A. Four times
- B. Two times
- C. Three times
- D. Six times
|
| 9 |
B2/2p is the expression of. |
- A. Lenz's law
- B. Magnetic energy
- C. Magnetic energy density
- D. Back emf
|
| 10 |
Lenz's law was given by Heinrich lenz in: |
- A. 1894
- B. 1904
- C. 1854
- D. 1834
|