Question

What is the dimensional formula of a solid angle?
(A) M¹L¹T¹
(B) M⁰L⁰T¹
(C) M¹L⁰T⁻²
(D) M⁰L⁰T⁰

Answer 1

Solid angle is a dimensionless quantity. Solid angle is defined as, R^2 * ∆(s.a.) = ∆(area subtended) So, ∆(s.a.) = ∆(area subtended)/R^2 Which means, ∆(s.a.) has a dimesnion of L^2/L^2, which equals L^0 Hence, it is dimensionless.

Answer 2

The dimensional formula of a solid angle is (D) M⁰L⁰T⁰.

• The solid angle is a dimensionless quantity that has no dimensional formula
• The formula of the solid angle(Ω) is, Ω=Ar2.
• Where Ω=Area of part of the spherical surface subtended divided by the radius of the area of the part of the spherical surface subtended.