For a short electric dipole, how does the electric field vary with distance \(r\) at a point on its axial line when \(r\gg\) length of the dipole?
1. \( \dfrac{1}{r}\)
2. \( \dfrac{1}{r^3}\)
3. \( \dfrac{1}{r^2}\)
4. \(r\)

Subtopic:  Electric Dipole |
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A dipole with moment \(\vec p\) is placed in a uniform electric field \(\vec E\). The torque acting on the dipole is given by:
1. \(\vec{\tau }=\vec{p}\cdot \vec{E}\)
2. \(\vec{\tau }=\vec{p} \times \vec{E}\)
3. \(\vec{\tau }=\vec{p}+ \vec{E}\)
4. \(\vec{\tau }=\vec{p}- \vec{E} \)

Subtopic:  Electric Dipole |
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AIPMT - 2001
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An electric dipole of dipole moment \({p}\) is aligned parallel to a uniform electric field \({E}.\) The energy required to rotate the dipole by \(90^\circ\) is:
1. \( p^2 E\)
2. \( p E\)
3. infinite
4. \( {pE}^2\)
Subtopic:  Electric Dipole |
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NEET - 2013
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Two electric dipoles of dipole moments \(1.2\times10^{-30}\) C-m and \(2.4\times10^{-30}\) C-m are placed in two different uniform electric fields of strengths \(5\times10^{4}\) NC–1 and \(15\times10^{4}\) NC–1 respectively. The ratio of maximum torque experienced by the electric dipoles is \( \dfrac{1}{x}.\) The value of \(x \) is:
1. \(2\)
2. \(4\)
3. \(6\)
4. \(8\)
Subtopic:  Electric Dipole |
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A point \(Q\) lies on the perpendicular bisector of an electric dipole of dipole moment \(p.\) If the distance of \(Q\) from the dipole is \(r\) (much larger than the size of the dipole), then the electric field at \(Q\) is proportional to:
1. \(p^{2}\) and \(r^{-3}\)
2. \(p\) and \(r^{-2}\)
3. \(p^{-1}\) and \(r^{-2}\)
4. \(p\) and \(r^{-3}\)

Subtopic:  Electric Dipole |
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AIPMT - 1998
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An electric dipole is placed in a uniform electric field of intensity \(2 \times 10^5 ~\text{N/C}\) at an angle of \(30^\circ.\) If it experiences a torque of \(4~\text{N-m},\) the charge on the dipole (dipole length \(=2~\text{cm}\)) is:
1. \( 7 ~\mu \text C\)
2. \(8 ~\text {mC} \)
3. \(2~\text {mC} \)
4. \( 5 ~\text {mC}\)
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An electric dipole consisting of two opposite charges of \(2\times10^{-6}~\text{C}\) each, separated by a distance of \(0.03~\text{m},\) is placed in an electric field of \(2\times10^5~\text{N/C}.\) The maximum torque on the dipole is:
1. \(12\times10^{-1}\) N-m
2. \(12\times10^{-3}\) N-m
3. \(24\times10^{-1}\) N-m
4. \(24\times10^{-3}\) N-m
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A point charge \(q\) is placed on the \(x\)-axis at \(x=a;\) an identical charge is placed on the \(y\)-axis at \(y=a.\) At the origin is placed a charge \((-2q).\) The dipole moment of the charge distribution is:
1. \(2qa\)

2. \(\sqrt2qa\)

3. \(\dfrac{qa}{2}\)

4. \(\dfrac{qa}{\sqrt2}\)
Subtopic:  Electric Dipole |
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If \(\vec{E}_{a x}\) and \(\vec{E}_{e q}\) represents an electric field at a point on the axial and equatorial line of a dipole. If points are at a distance \(r\) from the centre of the dipole, for \((r \gg a)\)

1. \(\vec{E}_{a x}=\vec{E}_{e q}\)
2. \(\vec{E}_{a x}=-\vec{E}_{e q}\)
3. \(\vec{E}_{a x}=-2 \vec{E}_{e q}\)
4. \(\vec{E}_{e q}=2 \vec{E}_{a x}\)
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The unit \(\text{C.m}\) (coulomb–metre) corresponds to which of the following physical quantities?

1.  Electric flux

2.  Electric potential

3.  Electric dipole moment

4.  Electric field intensity

Subtopic:  Electric Dipole |
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