Home
Class 12
PHYSICS
A rod lies across frictionless rails in ...

A rod lies across frictionless rails in a uniform magnetic field `vec(B)` as shown in figure. The rod moves to the right with speed `V`. In order to make the induced emf in the circuit to be zero, the magnitude of the magnetic field should

A

(a) not change

B

(b) increase linearly with time

C

( c) decrease linearly with time

D

(d) decrease nonlinearly with time

Text Solution

Verified by Experts

The correct Answer is:
D
(d) `Bl Vt = constant`
`B = ( C)/(lVt)`
Promotional Banner

Topper's Solved these Questions

  • ELECTROMAGNETIC INDUCTION

    CENGAGE PHYSICS ENGLISH|Exercise Exercises Multiple Correct|23 Videos

  • ELECTROMAGNETIC INDUCTION

    CENGAGE PHYSICS ENGLISH|Exercise Exercises Asserton - Reasoning|8 Videos

  • ELECTROMAGNETIC INDUCTION

    CENGAGE PHYSICS ENGLISH|Exercise Exercises Subjective|13 Videos

  • ELECTRICAL MEASURING INSTRUMENTS

    CENGAGE PHYSICS ENGLISH|Exercise M.C.Q|2 Videos

  • ELECTRON,PHONTS,PHOTOELECTRIC EFFECT & X-RAYS

    CENGAGE PHYSICS ENGLISH|Exercise dpp 3.3|15 Videos

Similar Questions

Explore conceptually related problems

A rod AB moves with a uniform velocity v in a uniform magnetic field as shown in figure

A conducting movable rod AB lies across the frictionless parallel conducting rails in a uniform magnetic field vecB whose magnitude at t=0 is B_(0) . The rod AB is given velocity v right ward and it continues to move with same velocity through out the motion [The acceleration due to gravity is along negative z- axis, i.e. vecg=10m//s^(2)(-hatk) , mass of rod =m .] Which of the following graphs will be the best representation of magnitude of magnetic field versus time.

A uniform conducting rod of length I is moving with speed v_0 in a uniform transverse magnetic field B_0 as shown in figure. The emf developed across the two ends of the rod will be

A small conducting rod of length l, moves with a uniform velocity v in a uniform magnetic field B as shown in fig __

A U - shaped conducting frame is fixed in space. A conducting rod CD lies at rest on the smooth frame as shown. The frame is in a uniform magnetic field B_0 which is perpendicular to be plane of the frame . At the time t = 0 , the magnitude of the magnetic field being to change with time t as, B =B_0/(1+kt) , where k is a positive constant . For no current to be ever induced in the frame the speed with which rod should be pulled starting from time t = 0 is (the rod CD should be moved such that its velocity must lie in the plane of frame and perpendicular to rod (CD)

A glass rod of length l moves with velocity v in a uniform magnetic field B. What is the e.m.f induced in the rod?

A conducting rod of length / is rotating about point Pin a uniform transverse magnetic field B_0 as shown in the figure. If angular speed of the rod is ω_0 then the magnitude of induced emf across the ends of the rod will be (PA = 2l/3 and PB = l/3)

A conductor of length 0.1m is moving with a velocity of 4m/ s in a uniform magnetic field of 2T as shown in the figure. Find the emf induced ?

A conductor of length 0.1m is moving with a velocity of 4m/s in a uniform magnetic field of 2T as shown in the figure. Find the emf induced ?

A semi-circular loop of radius R is placed in a uniform magnetic field as shown. It is pulled with a constant velocity. The induced emf in the loop is

CENGAGE PHYSICS ENGLISH-ELECTROMAGNETIC INDUCTION-Exercises Single Correct
  1. A rectangular loop of wire with dimensions shown in figure is coplanar...

    Text Solution

    |

  2. The four wire loops shown figure have vertical edge lengths of either ...

    Text Solution

    |

  3. A rod lies across frictionless rails in a uniform magnetic field vec(B...

    Text Solution

    |

  4. The current through the coil in figure (i) varies as shown in figure (...

    Text Solution

    |

  5. An electron moves on a straight line path XY the path show . The abcd ...

    Text Solution

    |

  6. In fig. there exists a uniform magnetic field B into the plane of pap...

    Text Solution

    |

  7. In figure, there is conducting ring having resistance R placed in the...

    Text Solution

    |

  8. In the space shown a non-uniform magnetic field vec(B) = B(0)(1+x)(-ha...

    Text Solution

    |

  9. There is a uniform magnetic field B in a circular region of radius R a...

    Text Solution

    |

  10. A gold rod of length l is accelerated in the horizontal direction wit...

    Text Solution

    |

  11. A square loop of side as and a straight long wire are placed in the sa...

    Text Solution

    |

  12. A wooden stick of length 3l is rotated about an end with constant angu...

    Text Solution

    |

  13. PQ is an infinite current carrying conductor. AB and CD are smooth con...

    Text Solution

    |

  14. Loop A of radius rgtgtR moves toward loop B with a constant velocity V...

    Text Solution

    |

  15. Figure. shows three rigions of magnetic field each of area A, and in e...

    Text Solution

    |

  16. a semicircle wire of radius R is rotated with constant angular velocit...

    Text Solution

    |

  17. Two identical cycle wheels (geometrically have different number of spo...

    Text Solution

    |

  18. A uniform magnetic field existsin region given by vec(B) = 3 hat(i) + ...

    Text Solution

    |

  19. Shows a square loop having 100 turns, an area of 2.5 X10^(-3) m^2 and...

    Text Solution

    |

  20. A and B two metallic rings pplaced at opposite sides of an infinitely ...

    Text Solution

    |