Question

2). an electric dipole is placed in a uniform electric field e of magnitude 2N/C, experiences maximum torque of magnitude 5 * 10^-3 . if charges of dipole have magnitude of 2mC then length of dipole is

1) 2m

2)6m

3)2.5 m

4)1.25 m

Answer 1

Answer:

6m

Explanation:

i think so

Answer 2

Answer:

The answer is 1.25 m (option d).

Explanation:

An electric dipole is a pair of charges which are equal in magnitude but opposite in sign and are separated by a distance d.

The product of the magnitude of charges and the distance between them is called the electric dipole moment (P).

P= q d

where,

q = magnitude of charge

d = Length of the dipole

When a uniform electric field is placed in a dipole, it experiences a torque and the expression of torque can be written as:

$\vec{T}^ =\vec{P} \times \vec{E} \\T =P E sin\theta$

where,

T = Torque

p= electric dipole moment

E = electric field

maximum torque is achieved at an angle of 90 degrees where $Sin \theta$ = 1

So according to the question,

maximum torque = $5\times 10^{-3} Nm$ =T

Electric field =  2 N/C = E

charge = 2mc = $2\times 10^{-3} C$=q

electric dipole = P = q d = $2d\times 10^{-3}$

So, putting all these in the formula of torque, we get:

$\vec{T}^ =\vec{P} \times \vec{E} \\T =P E sin\theta\\5\times 10^{-3} =2d\times 10^{-3} \times 2 \\d=1.25 m$

Therefore the length of the dipole is 1.25m.