Question

Which of the following is/are true about dipole?

(1) The unit of electric dipole moment is coulomb meter

(2) The net charge of the electric dipole is zero

(3) The net electric field due to an electric dipole is nonzero.

(4) Point diploe is the diploe with a small value of the charge.

1. Statement 1 & 2 only
2. All the above
3. Statement 1 & 3 only
4. Statement 1  only

Answer 1

Correct Answer - Option 2 : All the above

CONCEPT:

• An electric dipole is pair of equal and opposite charges separated by a distance of 2a, the midpoint of locations -q and + q is called the centre of the dipole.
• The total charge of an electric dipole is zero
• Electric dipole moment is the product of the magnitude of one charge multiplied by the distance of separation between the charge and is given by

⇒ P = 2a × q

Where P = dipole moment, 2a = Distance between the charge,and q = Charge

EXPLANATION:

• Electric dipole moment is the product of the magnitude of one charge multiplied by the distance of separation between the charge and is given by

⇒ P = 2a × q

• The unit of distance(a) is the meter and the unit of q is the coulomb, then the unit of dipole momentum is Coulomb meter, and the same can be calculated as

⇒ P = meter × Columb = Coulomb meter

• Hence, statement 1 is correct
• An electric dipole is pair of equal and opposite charges separated by a distance of 2a, the midpoint of locations -q and + q is called the centre of the dipole.
• The total charge on the dipole is 

⇒ q_total = q - q = 0 

• The total charge on the dipole is zero. Hence, statement 2 is correct.
• The total charge on the diploe is zero doesn't mean the total electric field is zero. The electric field due to the charge doesn't cancel out they only add up. Hence, statement 3 is correct
• As the value of charge tends to zero the diploe can be approximated as point diploe. Hence, statement 3 is correct 
• The answer will be the option that says all the statements are correct. Hence, option 2 is the answer