Home
Class 12
PHYSICS
In AC generator, induced emf is zero at ...

In AC generator, induced emf is zero at time t = 0. The induced emf at time `pi/(2omega)` is ____

A

`+V_m`

B

`-V_m`

C

zero

D

`+2 V_m`

Text Solution

Verified by Experts

The correct Answer is:
A
At time t=0 , the emf =0 , so emf obtained from eqn. `V=V_n sin omegat`
`therefore V=V_m sin (omegaxxpi/(2omega)) [ because t=pi/(2omega)]`
`therefore V=V_m sin (pi/2)`
`therefore V=+V_m [ because "sin" pi/2=1]`
Promotional Banner

Topper's Solved these Questions

  • ELECTROMAGNETIC INDUCTION

    KUMAR PRAKASHAN|Exercise Section D MCQs (MCQs asked in Competitive Exams )|38 Videos

  • ELECTROMAGNETIC INDUCTION

    KUMAR PRAKASHAN|Exercise Section C Ncert Exemplar Solution (Long Answer )|11 Videos

  • ELECTRIC CHARGES AND FIELDS

    KUMAR PRAKASHAN|Exercise SECTION D MCQS ASKED IN COMPETITIVE EXAMES (MCQS AKSED IN BOARD EXAM AND GUJCET)|14 Videos

  • ELECTROMAGNETIC WAVES

    KUMAR PRAKASHAN|Exercise BOARD.S QUESTION PAPER MARCH - 2020 (PART - B) SECTION - C|5 Videos

Similar Questions

Explore conceptually related problems

Why self induced emf is known as back emf ?

The magnitude of the induced emf is equal to the time rate of change of ……

Write different method to produce induced emf.

A coil having N turns and area A is rotating in uniform magnetic field then at time t, the magnetic flux associated with the coil is given by phi=NAB cos omegat . In the first rotation at time t = . . s, the induced emf is obtained maximum.

A straight line conductor of length 0.4 m is moved with a speed of 7 m/s perpendicular to a magnetic field of intensity 0.9 Wb/ m^2 . The induced emf across the conductor is ____

The magnitude of the induced emf is equal to the time rate of change of..

The flux linked with a coil at any instant 't' is given by phi=10t^2-50t+250 . The induced emf at t=3s is ____

Radius of a conducing wire r and its plane is perpendicular to magnetic field B. If the conductors is stretched and made in shape of square in its plane and in time t, then induced a emf epsilon is _____

If magnetic flux phi = (3t^2 - 2t + 5) Wb, then what is induced emf at t = 2 s.

KUMAR PRAKASHAN-ELECTROMAGNETIC INDUCTION-Section D MCQs (From DARPAN Based on Textbook )
  1. In one A.C. generator, brushes connected with slip rings become positi...

    Text Solution

    |

  2. Working principle of electric motor is to convert …...

    Text Solution

    |

  3. Voltage obtained in one A.C. generator V=V0 cos omegat . If V0 = 10 vo...

    Text Solution

    |

  4. A circular coil with radius 10 cm and 10 no. of tightly wound identica...

    Text Solution

    |

  5. A generator produces a voltage that is given by V = 240 sin 120t, wher...

    Text Solution

    |

  6. If an A.C. current of frequency 50 Hz is flowing through a conducting ...

    Text Solution

    |

  7. A coil having N turns and area A is rotating in uniform magnetic field...

    Text Solution

    |

  8. In an AC generator, the brushes in contact with the step rings alterna...

    Text Solution

    |

  9. The equation of A.C. voltage is given by V = 158 sin 200pit. The value...

    Text Solution

    |

  10. A coil with resistance 8 Omega and having 8 turns is connected with a...

    Text Solution

    |

  11. For the situation shown in the figure, what should be the value of for...

    Text Solution

    |

  12. For one coil, kept in 1T external magnetic field, current passing thro...

    Text Solution

    |

  13. As shown in figure a bar magnet suspended by a conducting spring is ma...

    Text Solution

    |

  14. Length of one metal rod is 1m. 2T is the intensity of the magnetic fie...

    Text Solution

    |

  15. The variation of induced emf E with time t in a coil when a short bar ...

    Text Solution

    |

  16. Current of 2A passing through a coil of 100 turns gives rise to a magn...

    Text Solution

    |

  17. A graph shown in the figure represents the variation of uniform magnet...

    Text Solution

    |

  18. In AC generator, induced emf is zero at time t = 0. The induced emf at...

    Text Solution

    |

  19. As shown in fig. a metal ring is held horizontally and a bar magnet is...

    Text Solution

    |

  20. A conducting loop of resistance R is pulled in a uniform magnetic fiel...

    Text Solution

    |