1Which of these has the same dimensions as emissivity?
Emissivity and magnetic susceptibility both have the dimensions [M⁰ L⁰ T⁰].
Heat and thermodynamicsClass 11, Thermal Properties of Matter
[M0 L0 T0]
Power radiated divided by the power a perfect black body would radiate, so it is a pure number.
Equal dimensions do not make them the same quantity. Compare emissivity with the others in the full grid.
1Which of these has the same dimensions as emissivity?
Emissivity and magnetic susceptibility both have the dimensions [M⁰ L⁰ T⁰].
2Which of these has no dimensions at all?
Emissivity is a ratio, so every power in its dimensional formula is zero.
3Which one has different dimensions from the others?
Heat is [M L² T⁻²]. The other three are all [M⁰ L⁰ T⁰].
The dimensional formula of emissivity is [M⁰ L⁰ T⁰]. It comes from emissivity = power / power.
Emissivity has no unit, because it is a pure number.
Yes. Emissivity is a ratio of like quantities, so every power in its dimensional formula is zero: [M⁰ L⁰ T⁰].