Question 278: Centre of Mass and Rotational Motion

Question

An electric dipole is formed by two equal and
opposite charges q with separation d. The
charges have same mass m. It is kept in a
uniform electric field E. If it is slightly rotated
from its equilibrium orientation, then its angular
frequency $$\omega$$ is :-

Accepted Answer

Moment of inertia
$$(I) = m{\left( {{d \over 2}} ight)^2} 	imes 2 = {{m{d^2}} \over 2}$$
Now by $$	au  = l\alpha $$
$$(qE)(d\,\sin 	heta ) = {{m{d^2}} \over 2}.\alpha $$
$$\alpha  = \left( {{{2qE} \over {md}}} ight)\sin 	heta $$ for small $$	heta $$
$$ \Rightarrow \alpha  = \left( {{{2qE} \over {md}}} ight)	heta $$
$$ \Rightarrow $$ Angular frequency $$\omega  = \sqrt {{{2qE} \over {md}}} $$

Answer

$$\sqrt {{{qE} \over {md}}} $$

Answer

$$\sqrt {{{qE} \over {2md}}} $$

Answer

$$\sqrt {{{qE} \over {-2md}}} $$

Answer

$$\sqrt {{{2qE} \over {md}}} $$

Centre of Mass and Rotational Motion

An electric dipole is formed by two equal and opposite charges q with separation d. The charges have same mass m. It is kept in a uniform electric field E. If it is slightly rotated from its equilibrium orientation, then its angular frequency $\omega$ is :-

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