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Dipole moment of coil is 2hati+3hatj+5ha...

Dipole moment of coil is `2hati+3hatj+5hatk`. If this coil is placed in uniform magnetic field having magnitude `3hatkT`, torque acting on it is _____ Nm.

A

`sqrt35`

B

`sqrt117`

C

`sqrt25`

D

`sqrt135`

Text Solution

Verified by Experts

The correct Answer is:
B
`vectau=vecmuxxvecB=|(hati,hatj,hatk),(2,3,5),(0,0,3)|`
`vectau=9hati-6hatj+0hatk=9hati-6hatj`
`|vectau|=sqrt(81+36)`
`therefore|vectau|=sqrt117`
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KUMAR PRAKASHAN-MOVING CHARGES AND MAGNETISM-SECTION D (MULTIPLE CHOICE QUESTIONS)
  1. A rectrangular coil 20cmxx20cm has 100 turns and carries a current of ...

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  2. A current carring small loop behaves like a small magnet. If A be its ...

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  3. Dipole moment of coil is 2hati+3hatj+5hatk. If this coil is placed in ...

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  4. A circular coil of radius 4 cm and of 20 turns carries a current of 3 ...

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  5. An electron moves with a constant speed v along a circle of radius r. ...

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  6. A circular coil having N turns is made from a wire L meter long. If a ...

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  7. can measure small current and small voltage both.

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  8. has maximum resistance.

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  9. Why small soft iron cylinder is placed at the axis of the coil in galv...

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  10. What should be the resistance of an ideal ammeter ?

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  11. When series resistance is increased, range of voltmeter

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  12. When shunt connected to galvanometer has the value equal to resistance...

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  13. Which of following statements is wrong?

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  14. There are three voltmeters of same range with resistance 10,000Omega,8...

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  15. In order to increase the sensitivity of a moving coil galvanometer, s...

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  16. If range of an ammeter with resistance 5Omega is to be made double the...

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  17. is known as current sensitivity of a galvanometer.

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  18. is known as voltage sensitivity of galvanometer.

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  19. Relation between voltage sensitivity (sigma(v)) and current sensitivit...

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  20. When 50Omega resistance is connected to one voltmeter, its range is ob...

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