Home
Class 12
PHYSICS
A current of 6A flows through a coil whe...

A current of 6A flows through a coil when connected to a 24 volt d.c. supply. To get the same current with a 50 Hz a.c. supply, the voltage required is 30 V. What is the power factor of the coil?

A

`2/5`

B

`4/5`

C

`5/6`

D

`3/5`

Text Solution

Verified by Experts

The correct Answer is:
B
`R = 24/6 = 4 Omega and Z = 30/6 = 5Omega`
`:.` Power factor = `cos theta = R/Z = 4/5`.
Promotional Banner

Topper's Solved these Questions

  • ELECTROMAGNETIC INDUCTION AND ALTERNATING CURRENTS

    MARVEL PUBLICATION|Exercise TEST YOUR GRASP - 16|30 Videos

  • ELASTICITY

    MARVEL PUBLICATION|Exercise Test Your Grasp - 5|15 Videos

  • ELECTRONS AND PHOTONS

    MARVEL PUBLICATION|Exercise TEST YOUR GRASP - 17|15 Videos

Similar Questions

Explore conceptually related problems

Calculate the current flowing through a heater rated at 2kW when connected to a 300V d.c. supply.

Calculate the current flowing through a heater rated at 2 kW when connected to a 300V d.c. supply.

A current of 4 A flows in a coil when connected to a 12 V dc source. If the same coil is connected to a 12 V, 50 rad s^(-1) ac source, a current of 2.4 A flows of the coil in the circuit. The power developed in the circuit of a 2500 (mu)F capacitor that is connected in series with the coil is

A current of 4 A flows in a coil when connected to a 12 V dc source. If the same coil is connected to a 12 V, 50 rad s^(-1) ac source, a current of 2.4 A flows of the coil in the circuit. The inductance of the coil is

A bulb is connected to a 100 V DC supply . It is found that the current of 5 A flows in the circuit. The same bulb is connected to an AC supply at 120 V . The frequency of source is 50 Hz. Calculate the inductance of coil required so that the lamp glows in an AC circuit too.

A current of 6 A flows in a coil when connected to a dc source of 18 V. If the same coil is connected to an ac source of 20 V, 50 rad/s, a current of 4 A flows in the circuit. The inductance of the coil is 10x mH. Find out the value of x.

A current of 5 A flows through a conductor 25 ^@C , when connected to a power supply of 100 V . At what temperature the current will drop to 2A , if it remains connected to the power supply (Temperature coefficient of conductor is 0.005 ^@C^(-1) .)

An electric heater consumes 1 kilowatt power when connected across a 100 volt. D.C. supply. If this heater is to be used with 200V , 50Hz A.C. supply, the value of inductance to be connected in series with it is

A current of 4A flows in a coil when connected to a 12V DC source. If the same coil is connected to a 12V, 50 rad//s AC source, a current of 2.4A flows in the circuit. Determine the inductance of the coil. Also, find the power developed in the circuit if a 2500muF capacitor is connected in series with the coil.

A current of 1 A flows through a coil, when a 100 V d.c. is applied to it. But a current of 0.5 A flows through the same coil, when a 100V a.c. of frequency 50 Hz is applied. The resistance and inductance of the coil are given by (take pi^(2)=10 )

MARVEL PUBLICATION-ELECTROMAGNETIC INDUCTION AND ALTERNATING CURRENTS -TEST YOUR GRASP - 16
  1. A current of 6A flows through a coil when connected to a 24 volt d.c. ...

    Text Solution

    |

  2. A coil having an area of 2m^(2) is placed in a magnetic field which ch...

    Text Solution

    |

  3. A straight conductor of length 2 is moves a velocity of 2 m//s, in a m...

    Text Solution

    |

  4. The magnetic flux passing perpendicular to the plane of a coil given b...

    Text Solution

    |

  5. Two identical circular loops of metal wire are lying on a table withou...

    Text Solution

    |

  6. A telegraph wire of length 2500m, is kept in E-W direction, at a heigh...

    Text Solution

    |

  7. When the current in a coil changes from 2A to 4A in 0.05 sec, the e.m....

    Text Solution

    |

  8. Two coil A and B are placed in a circuit. When current changes by 8 Am...

    Text Solution

    |

  9. Two coils P and S have a mutual inductance of 5 xx 10^(-3)H. If the cu...

    Text Solution

    |

  10. The primary and secondary voltage of an ideal step down transformer ar...

    Text Solution

    |

  11. A step down transformer has a turn ratio of 20 : 1. If 8 volt are deve...

    Text Solution

    |

  12. A step down transformer of efficiency 80% is used on a 1000V line to d...

    Text Solution

    |

  13. A coil 10 turns and area 10^(-2)m^(2) rotates in a magnetic field of 0...

    Text Solution

    |

  14. An alternating e.m.f. is given by E=10 cos omega t. If the frequency i...

    Text Solution

    |

  15. In an A.C. Circuit, the current is given by I=6 sin(200 pi t+(pi)/6)...

    Text Solution

    |

  16. An alternating e.m.f. given by e=200 sin 50 t is applied to a circuit ...

    Text Solution

    |

  17. An alternating voltage is represented by V=80 sin(100 pi t)cos(100 p...

    Text Solution

    |

  18. In an A.C. circuit, E=100 sin (500 t) volt and I=1000 sin(500 t +(pi)/...

    Text Solution

    |

  19. In an A.C. circuit, a resistance R=40 Omega and an inductance L are c...

    Text Solution

    |

  20. The inductance of a coil is 10 H. What is the ratio of its reactance w...

    Text Solution

    |

  21. For tuning radio and T.V. circuits, series resonance circuits are used...

    Text Solution

    |