49685d02_nt_Convention___iusmentis_com___Basis_in_priority_document
[Claim] The lamp of claim 1, being coupled to an on/off-switch. [Benefit of priority?] Yes. The term "powered on" implies the presence of an on/off-switch. No. "Powering on" can also be done by plugging in the power cord. [Basis in priority document] 
"When the lamp is powered on, ..."
Priority under the European Patent Convention (EPC) (in Patents > European Patent Convention @ iusmentis.com)
Basis in priority document