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A long solenoid has 200 turns per cm and carries a current i. The magnetic field at its centre is 6.28 x 10-2 weber/m2. Another long solenoid has 100 turns per cm and it carries a current i/3. The value of the magnetic field at its centre is

  • Option 1)

    1.05\: \times 10^{-4}\; Wb/m^{2}

  • Option 2)

    1.05\: \times 10^{-2}\; Wb/m^{2}

  • Option 3)

    1.05\: \times 10^{-5}\; Wb/m^{2}

  • Option 4)

    1.05\: \times 10^{-3}\; Wb/m^{2}

 

Answers (1)

best_answer

As we learnt in

Magnetic field due to Infinite length solenoid -

\alpha =\beta =\frac{\pi }{2}

 Bin=\mu _{o}ni

- wherein

Point is well inside the solenoid 

 

 

In first case,  B_{1}=\mu _{0}n_{1}I_{1}

In second case,  B_{2}=\mu _{0}n_{2}I_{2}

\therefore \; \; \; \frac{B_{2}}{B_{1}}=\frac{n_{2}}{n_{1}}\times \frac{I_{2}}{I_{1}}=\frac{100}{200}\times \frac{i/3}{i}=\frac{1}{6}

\therefore \; \; \; B_{_{2}}=\frac{B_{1}}{6}=\frac{6.28\times 10^{-2}}{6}

=1.05\; \times \; 10^{-2}\; Wb/m^{2}


Option 1)

1.05\: \times 10^{-4}\; Wb/m^{2}

Incorrect option

Option 2)

1.05\: \times 10^{-2}\; Wb/m^{2}

Incorrect option

Option 3)

1.05\: \times 10^{-5}\; Wb/m^{2}

Incorrect option

Option 4)

1.05\: \times 10^{-3}\; Wb/m^{2}

Incorrect option

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Plabita

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