Lamp or bulb matters not, when you go to B&Q and ask where the 50 watt bulbs are you'll be directed to the electrical section and not the gardening section, similarly if you are seeking tulip bulbs you'll be directed to gardening not electrical. You may be unlucky and you have asked the retired electrician working as customer service and get a lecture of how electricians call them lamps listen and nod politely and them go and get your 50 watt bulb. Should you ask for a 50 watt lamp you'll still be directed to the electrical section but the aisle with the reading lamps, wall lamps etc unless it's the retired electrician again, he/she will recognise a fellow electrician and you will get served personally (the lamp thing is the electricians version of the masons handshake)