NEET Physics Question - Electrostatics

An electric dipole with dipole moment \( 2\times 10^{-9} \)Cm is aligned at 30º with the direction of a uniform electric field of magnitude \( 4\times 10^{4} NC^{-1}\). The magnitude of the torque acting on the dipole is :

\[ 2\times 10^{-5} Nm\]

\[ 2\times 10^{-4} Nm\]

\[ 4\times 10^{-4} Nm\]

\[ 4\times 10^{-5} Nm\]

Solution:

Given:
- Dipole moment: \( p = 2 \times 10^{-9} \, \text{C·m} \)
- Electric field: \( E = 4 \times 10^{4} \, \text{N/C} \)
- Angle: \( \theta = 30^\circ \)

Torque (\( \tau \)):
\[
\tau = pE \sin\theta
\]
\[
\tau = (2 \times 10^{-9})(4 \times 10^{4}) \sin 30^\circ
\]
\[
\tau = (8 \times 10^{-5}) \times \frac{1}{2} = 4 \times 10^{-5} \, \text{N·m}
\]

Final Answer:
\[
\tau = 4 \times 10^{-5} \, \text{N·m}
\]

Rankers Physics

Solution:

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