Three solid copper spheres, X, Y and Z, are heated to the same temperature. Sphere X has diameter $2d$ and a black surface. Sphere Y has diameter $d$ and a white surface. Sphere Z has diameter $2d$ and a white surface. Which row shows the sequence for the rate of emission of radiation?
- Ahighest: X, second highest: Y, lowest: Z
- Bhighest: X, second highest: Z, lowest: Y
- Chighest: Z, second highest: X, lowest: Y
- Dhighest: Z, second highest: Y, lowest: X