Question

Two short magnetic dipoles m₁ and m₂ each having a magnetic moment of 1 Am² are placed at points O and P respectively. The distance between OP is 1 metre. The torque experienced by the magnetic dipole m₂ due to the presence of m₁ is ______ × 10^-7 Nm.

Options

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Answer 1

Two short magnetic dipoles m₁ and m₂ each having a magnetic moment of 1 Am² are placed at points O and P respectively. The distance between OP is 1 metre. The torque experienced by the magnetic dipole m₂ due to the presence of m₁ is 1 × 10^-7 Nm.

Explanation:

Because magnetic dipole (2) is in (1)'s magnetic field, it will experience torque.

`tau = (m_2 xx B_1)sin 90^circ`

`tau = m_2B_1`

Magnetic Dipole (2) is in the dipole's equatorial position (1). 

So, `B_1 = (mu_0)/(4pi) xx (m_1)/(r^3)`

= `(mu_0)/(4pi) . 1/1^3`

The torque `tau = 1 xx (mu_0)/(4pi) xx 1`

= `1 xx 10^-7` N.m