NEET 2023, Physics Q7: Coulomb's Law And Electric Field

NEET2023Physics

An electric dipole is placed at an angle of $3 0^{\circ}$ with an electric field of intensity $2 \times 1 0^{5}$ NC $^{- 1}$ . It experiences a torque equal to $4$ N m. Calculate the magnitude of charge on the dipole, if the dipole length is $2$ cm.

A
$6$ mC
B
$4$ mC
C
$2$ mC
D
$8$ mC

Solution

Torque on a dipole: $τ = pE sin θ = q L E sin θ$ .

$4 = q \times (2 \times 1 0^{- 2}) \times (2 \times 1 0^{5}) \times 0.5$

$\Rightarrow q = \frac{4}{2000} = 2 \times 1 0^{- 3}$ C $= 2$ mC.

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NEET 2023, Physics Q7: Coulomb's Law And Electric Field

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