A short bar magnet placed with its axis at with an external field of 800 Gauss experiences a torque of 0.016 N.m. The work done in moving it from the most stable to the most unstable position is . The value of is _______. [2026]

Question

A short bar magnet placed with its axis at $30 °$ with an external field of 800 Gauss experiences a torque of 0.016 N.m. The work done in moving it from the most stable to the most unstable position is $α \times 10^{- 3} J$ . The value of $α$ is _______. [2026]

Smart Achievers · Accepted Answer

(64)

$τ = μ B \sin θ \Rightarrow 0.016 = μ \times B \times \frac{1}{2}$

$\Rightarrow μ = \frac{0.032}{B}$

$W_{ext} = U_{f} - U_{i} = μ B - (- μ B) = 2 μ B$

$= 2 \times \frac{0.032}{B} \times B$

$= 0.064 J$

Solution

Q.
A short bar magnet placed with its axis at $30 °$ with an external field of 800 Gauss experiences a torque of 0.016 N.m. The work done in moving it from the most stable to the most unstable position is $α \times 10^{- 3} J$ . The value of $α$ is _______. [2026]

Ans.
(64)

$τ = μ B \sin θ \Rightarrow 0.016 = μ \times B \times \frac{1}{2}$

$\Rightarrow μ = \frac{0.032}{B}$

$W_{ext} = U_{f} - U_{i} = μ B - (- μ B) = 2 μ B$

$= 2 \times \frac{0.032}{B} \times B$

$= 0.064 J$

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Solution

Q. A short bar magnet placed with its axis at 30° with an external field of 800 Gauss experiences a torque of 0.016 N.m. The work done in moving it from the most stable to the most unstable position is α×10-3 J. The value of α is _______. [2026]

Ans. (64) τ=μBsinθ ⇒ 0.016=μ×B×12 ⇒μ=0.032B Wext=Uf-Ui=μB-(-μB)=2μB =2×0.032B×B =0.064 J

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Q.
A short bar magnet placed with its axis at $30 °$ with an external field of 800 Gauss experiences a torque of 0.016 N.m. The work done in moving it from the most stable to the most unstable position is $α \times 10^{- 3} J$ . The value of $α$ is _______. [2026]

Ans.
(64)

$τ = μ B \sin θ \Rightarrow 0.016 = μ \times B \times \frac{1}{2}$

$\Rightarrow μ = \frac{0.032}{B}$

$W_{ext} = U_{f} - U_{i} = μ B - (- μ B) = 2 μ B$

$= 2 \times \frac{0.032}{B} \times B$

$= 0.064 J$