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An electric current passes through a lon...

An electric current passes through a long straight wire. At a distance 5 cm from the wire the magnetic field is `B`. The field at 20 cm from the wire would be

A

2B

B

B/4

C

B/2

D

B

Text Solution

Verified by Experts

The correct Answer is:
B
`B prop 1/r`
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NARAYNA-MOVING CHARGES AND MAGNETISM-EXERCISE - 1(C.W) (AMPERE.S CIRCUITAL LAW BIOT-SAVART LAW AND ITS APPLICATIONS)
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  2. A closed circuit is in the form of a regular hexagon of side r. If the...

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  3. A current of 1//(4pi) ampere is flowing in a long straight conductor. ...

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  4. A wire in the form of a square of side '2m' carries a current 2A. Then...

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  5. An electric current passes through a long straight wire. At a distanc...

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  6. A current of one ampere is passed through a straight wire of length 2*...

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  7. A straight vertical conductor carries a current. At a point 5cm due no...

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  8. A circular coil of radius 25cm, carries a current of 50 ampere. If it ...

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  9. A circular coil of radius R carries a current i. The magnetic field at...

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  10. Two circular coils are made of two identical wires of same length and ...

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  11. Two circular coils have diameters 10cm and 20cm with same number of tu...

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  12. A wire carrying a current of 4A is in the form of the circle. It is ne...

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  13. Two concentric circular coils A and B have radii 25cm and 15cm and ca...

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  14. A wire carrying a current of 140 ampere is bent into the form of a cir...

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  15. The magnetic induction at a point at a large distance d on the axial l...

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  16. A particle having charge 100 times that of an electron is revolving in...

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  17. A battery is connected between two points A and B on the circumference...

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