Q.

Depending on the radiating properties, a body will be black when (Where a = absorptivity, p = reflectivity, X = transmissivity.)

• AP = 0, x = 0 and a = 1
• BP= 1, T = 0 and a = 0
• CP = 0, x = 1 and a = 0
• DX = 0, a + p = 0