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________ is the dimensional formula for electric dipole moment.

Asked in GSEB Board August 2020 · Units and dimensions

• (1) M⁰L¹T⁻¹A¹
• (2) M⁰L¹T⁻¹A⁻¹
• (3) M⁰L¹T¹A¹
• (4) M⁰L⁻¹T¹A¹

Step-by-step solution

Why the other options are wrong

• (1) M⁰L¹T⁻¹A¹ has the sign of the time exponent reversed. The charge is q=It, so the time multiplies in and the exponent comes out +1; a T⁻¹ would mean dividing by the time.
• (2) M⁰L¹T⁻¹A⁻¹ inverts both the current and the time, so it is d/q -- separation per unit charge -- instead of qd.
• (4) M⁰L⁻¹T¹A¹ puts the length in the denominator, as if the dipole moment were the charge divided by the separation. It is the product: pulling the two charges further apart makes the dipole stronger, not weaker.

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