Question

A dipole of dipole moment 5 × 10–6 C m is placed in a uniform electric field . If angle between dipole moment and electric field is 30°, the torque acting on it is
a)2.5 Nm
b)0.25 Nm
c)5 Nm
d)0.5 Nm2.5 Nm

Answer 1

Given:

A dipole of dipole moment 5 × 10–6 C m is placed in a uniform electric field 10^(6) . If angle between dipole moment and electric field is 30°.

To find:

Torque acting on the Dipole.

Calculation:

Torque acting on a Dipole can be calculated from cross-product between Dipole Moment and Electrostatic field intensity.

$\therefore \: \vec{ \tau} = \vec{P} \times \vec{E}$

$= > | \vec{ \tau}| = P \times E \times \sin( \theta)$

$= > | \vec{ \tau}| = (5 \times {10}^{ - 6} )\times E \times \sin( 30 \degree)$

$= > | \vec{ \tau}| = (5 \times {10}^{ - 6} )\times E \times \dfrac{1}{2}$

$= > | \vec{ \tau}| = (5 \times {10}^{ - 6} )\times {10}^{6} \times \dfrac{1}{2}$

$= > | \vec{ \tau}| =2.5 \: Nm$

So, final answer is:

$\boxed{ \sf{ \red{ \large{ | \vec{ \tau}| =2.5 \: Nm }}}}$

Answer 2

Answer:

given  =

dipole moment = 5 ×10⁻⁶ cmθ

angle { θ }  = 30 °

to find =  torque

solution ;

              τ = E sinθ

               τ=  5 × 10  ⁻⁶ˣ  1/2

              τ  =   2.5 χ 10 ⁻⁶  Nm

so, option 1st is correct