VIT - VITEEE 2025
National level exam conducted by VIT University, Vellore | Ranked #11 by NIRF for Engg. | NAAC A++ Accredited | Last Date to Apply: 31st March | NO Further Extensions!
Dipole in Uniform electric field is considered one of the most asked concept.
36 Questions around this concept.
An electric dipole is placed at an angle of 30o to a non- uniform electric field. The dipole will experience
Two identical electric point dipoles have dipole moments $\overrightarrow{p_1}=\hat{p i}$ and $\overrightarrow{p_2}=-p \hat{i}$ and are held on the x-axis at distance 'a' from each other. When released, they move along the $x$-axis with the direction of their dipole moments remaining unchanged. If the mass of each dipole is ' $m$ ', their speed when they are infinitely far apart is :
When an electric dipole $\vec{p}$ is placed in a uniform electric field $\vec{E}$ then at what angle between $\vec{p}$ and $\vec{E}$ the value of torque will be maximum
JEE Main 2025: City Slip Link | Study Plan | Official Question Paper (Session 1)
JEE Main 2025: Sample Papers | Mock Tests | PYQs | High Scoring Topics | College Predictor
New: Meet Careers360 experts in your city and get guidance on shortlisting colleges
Apply to TOP B.Tech /BE Entrance exams: VITEEE | MET | AEEE | BITSAT
If a dipole is slightly displaced from its stable equilibrium position then which of the following is true -
An electric dipole placed in a non-uniform electric field can experience
Two electric dipoles of dipole moments $1.2 \times 10^{-30} \mathrm{Cm}$ and $2.4 \times 10^{-30} \mathrm{Cm}$ are placed in two different uniform electric fields of strengths $5 \times 10^4 \mathrm{NC}^{-1}$ and $15 \times 10^4 \mathrm{NC}^{-1}$ respectively. The ratio of maximum torque experienced by the electric dipoles will be $\frac{1}{\mathrm{x}}$. The value of x is______.
The torque acting on an electric dipole placed in an electric field is maximum when the angle between the electric field and the dipole moment is _______.
National level exam conducted by VIT University, Vellore | Ranked #11 by NIRF for Engg. | NAAC A++ Accredited | Last Date to Apply: 31st March | NO Further Extensions!
Ranked #42 among Engineering colleges in India by NIRF | Highest CTC 50 LPA , 100% Placements | Last Date to Apply: 28th March
Net Force-
When a dipole is kept in a uniform electric field. The net force experienced by the dipole is zero as shown in the below figure.
I.e $F_{\text {net }}=0$
Hence dipole will not make any linear motion.
Torque on dipole-
Net torque about the center of dipole is given as $\tau=Q E d \sin \theta$
Using $P=Q d_{\text {we get }} \tau=P E \sin \theta$
So $\vec{\tau}=\vec{P} \times \vec{E}$
- The direction of the torque is normal to the plane containing dipole moment $P$ and electric field $E$ and is governed by right-hand screw rule.
- If Dipole is parallel to E the torque is Zero. I.e $\Theta=0^{\circ} \quad \tau=0$ (This is the position of stable equilibrium of dipole)
Oscillation of dipole -If a dipole experiencing a torque in an electric field is allowed to rotate, then it will rotate to align itself to the Electric field. But when it reaches along the direction of E the torque becomes zero. But due to inertia, it overshoots this equilibrium condition and then starts oscillating about this mean position.
The time period of this oscillation is given as
$
T=2 \pi \sqrt{\frac{I}{P E}}
$
where $\mathrm{I}=$ moment of inertia of dipole about the axis passing through its center and perpendicular to its length.
"Stay in the loop. Receive exam news, study resources, and expert advice!"