Home
Class 12
PHYSICS
When a wire loop is rotated in a magneti...

When a wire loop is rotated in a magnetic field the direction of induced emf changes once in each .....

A

`1/4` revolution

B

`1/2` revolution

C

1 revolution

D

2 revolution

Text Solution

Verified by Experts

The correct Answer is:
B
`phi=NABomega sin omegat`
`therefore (dphi)/(dt)=NABomega sin omegat`
In half revolution `omegat` becomes,
`omega(t+T/2)=omegat+(omegaT)/2`
`=omegat+(2pi)/T. T/2`
`=omegat+pi`
Promotional Banner

Topper's Solved these Questions

  • ALTERNATING CURRENTS

    KUMAR PRAKASHAN|Exercise SECTION-D MCQs (DARPAN BASED ON TEXTBOOK)|188 Videos

  • ATOMS

    KUMAR PRAKASHAN|Exercise Section-D -MCQs asked in GUJCET / Board Exam|34 Videos

Similar Questions

Explore conceptually related problems

Choose the corret option : A rectangular coil of copper wires is rotated in a magnetic field . The direction of the induced current changes once in each ……

As shown in the following figure , the magnetic force is acting in the downward direction on the current - carrying wire placed in the magnetic field . What is the direction of the magnetic field ?

Figure shows planar loops of different shapes moving out of or into a region of a magnetic field which is directed normal to the plane of the loop away from the reader. Determine the direction of induced current in each loop using Lenz's law.

Figure shows planar loops of different shapes moving out of or into a region of a magnetic field which is directed normal to the plane of the loop away from the reader. Determine the direction of induced current in each loop using Lenz’s law.

When a wire is moved up and down in a magnetic field , a current is indcued in the wire . What is this phenomenon known as ?

When current is increasing in the coil, the direction of induced emf is ….. the direction of current.

When current passing through a coil increases, direction of induced emf is

Inside a bar magnet the direction of the magnetic field lines is….. .

Show magnetic field lines due to current carrying loop.

The given loop is kept in a uniform magnetic field perpendicular to the plane of the loop. The field changes from 1000 Gauss to 500 Gauss in 5 seconds. The average induced emf in the loop is

KUMAR PRAKASHAN-ALTERNATING CURRENTS -SECTION-D MCQs (COMPETITIVE EXAMS)
  1. The phase difference between current and voltage for L-C-R A.C. series...

    Text Solution

    |

  2. The value of capacitive reactance of capacitor XC. If the values of ca...

    Text Solution

    |

  3. When a wire loop is rotated in a magnetic field the direction of induc...

    Text Solution

    |

  4. In L-C-R circuit, the energy dissipated in …….

    Text Solution

    |

  5. The voltage of an A.C. source varies with time according to the equati...

    Text Solution

    |

  6. A L-C-R circuit connected to an A.C. source of frequency f. If current...

    Text Solution

    |

  7. A series R-C circuit is connected to an alternating voltage source. Co...

    Text Solution

    |

  8. Which of the following combinations should be selected for better tuni...

    Text Solution

    |

  9. The potential differences across the resistance, capacitance and induc...

    Text Solution

    |

  10. A small signal voltage V(t) = V0 sinomegat is applied across an ideal...

    Text Solution

    |

  11. An inductor 20 mH, a capacitor 50 muF and a resistor 40Omega are conne...

    Text Solution

    |

  12. An inductor 20 mH, a capacitor 100 muF and a resistor 50 Omega are con...

    Text Solution

    |

  13. For the reading obtained in ideal voltmeters and ammeters in above cir...

    Text Solution

    |

  14. An alternating voltage V = V0 sinomegat is applied across a circuit. A...

    Text Solution

    |

  15. In an A.C. circuit the ratio of inductive reactance and capacitive rea...

    Text Solution

    |

  16. A transformer has an efficiency of 80%. It works at 100 V and 4kW. If ...

    Text Solution

    |

  17. In an A.C. circuit, a resistor of ROmega is connected in series with a...

    Text Solution

    |

  18. At time t = 0 s, voltage of an A.C. generator starts from 0 V and beco...

    Text Solution

    |

  19. In a series resonant circuit, the A.C. voltages across resistance R, i...

    Text Solution

    |

  20. What is the average power dissipation in an ideal capacitor in A.C. ci...

    Text Solution

    |