Home
Class 12
PHYSICS
A trensformer is used to light 140 W, 2...

A trensformer is used to light 140 W, 24 V lamp from a 240 V ac mains. If the main current is 0.7 A, the efficiency of the transformer is

A

`48%`

B

`63.8%`

C

`83.3%`

D

`90%`

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Topper's Solved these Questions

  • ALTERNATING CURRENT

    RESONANCE ENGLISH|Exercise Exercise -2 Part-1|14 Videos

  • ALTERNATING CURRENT

    RESONANCE ENGLISH|Exercise Exercise -2 Part-2|6 Videos

  • ALTERNATING CURRENT

    RESONANCE ENGLISH|Exercise HIGH LEVEL PROBLEMS|11 Videos

  • ATOMIC PHYSICS

    RESONANCE ENGLISH|Exercise Advanved level problems|17 Videos

Similar Questions

Explore conceptually related problems

A transformer is used to light a 100 W and 110 V lamp from a 220V mains. If the main current is 0.5 A , the Efficiency of the transformer is approximately:

A transformer is used to light a 100 W and 110 V lamp from a 220V mains. If the main current is 0.5 A , the Efficiency of the transformer is approximately:

A transformer is used to light a 100 W and 110 V lamp from a 220V mains. If the main current is 0.5 A , the Efficiency of the transformer is approximately:

A transformer is used to light a 100 W and 110 V lamp from a 220 V (Mains). If the main current is 0.5 A, the efficiency of the transformer is approximately

A transformer is used to light a 140 W, 24 V lamp from 240 V AC mains. The current in mains cable is 0.7 A, find the efficiency of transformer.

A transformer is used to light a 140 W, 24 V lamp from 240 V AC mains. The current in mains cable is 0.7 A, find the efficiency of transformer.

A step-down transformer is used on a 1000 V line to deliver 20A at 120V at the secondary coil. If the efficiency of the transformer is 80% the current drawn from the line is.

A transformer is employed to reduce 220V to 11V . The primary draws a current of 5A and the secondary 90A . The efficiency of the transformer is

A step down transformer converts transmission line voltage from 11000 V to 220 V. The primary of the transformer has 6000 turns and efficiency of the transformer is 60%. If the output power is 9 kW, then the input power will be

A current of 2A is flowing at 220 V in the primary coil of a transformer. If current in the secondary coil is 1 A and efficiency of the transformer is 80% then the voltage produced in the secondary coil will be

RESONANCE ENGLISH-ALTERNATING CURRENT-Exercise -1 Part-1
  1. An alternating voltage E=200sqrt(2)sin(100t) is connected to a 1 micro...

    Text Solution

    |

  2. When 100 V DC is applied across a solenoid, a steady current of 1 A fl...

    Text Solution

    |

  3. In an L-C-R circuit the AC voltage across R, L and C comes out as 10 V...

    Text Solution

    |

  4. In the series L-C-R circuit , the voltmeter and ammeter readings are

    Text Solution

    |

  5. For a series LCR circuit the power loss at resonance is : -

    Text Solution

    |

  6. A series LCR circuit containing a resistance of 120 ohm has angular re...

    Text Solution

    |

  7. In an LCR circuit, the capacitance is made one-fourth, when in resonan...

    Text Solution

    |

  8. An inductance L , a capacitor of 20muF and a resistor of 10Omega are c...

    Text Solution

    |

  9. A resistor R, an inductor L, a capacitor C and voltmeters V(1),V(2) an...

    Text Solution

    |

  10. A power transformer (step up) with an 1:8 turns ratio has 60 Hz,120 V ...

    Text Solution

    |

  11. A trensformer is used to light 140 W, 24 V lamp from a 240 V ac mains...

    Text Solution

    |

  12. In a step-up transformer the voltage in the primary is 220 V and the c...

    Text Solution

    |

  13. The core of a transformer is laminated to reduce

    Text Solution

    |

  14. A capacitor is a perfect insulator for

    Text Solution

    |

  15. A choke coil has

    Text Solution

    |

  16. A choke coil is preferred to a rheostate in AC circuit as

    Text Solution

    |

  17. With increase in frequency of an AC supply, the inductive reactance:

    Text Solution

    |

  18. With increase in frequency of an AC supply, the capacitive reactance:

    Text Solution

    |

  19. An AC ammeter is used to measure current is a circuit . When a given d...

    Text Solution

    |

  20. In an a.c. circuit consisting of resistance R and inductance L, the vo...

    Text Solution

    |