The moderator reminded the Red Bull driver about his language at the time during the Thursday conference organised by the governing FIA.
Stewards summoned Verstappen on Friday for an alleged breach of the international sporting code.
They said in a statement that Verstappen apologised for his behaviour and explained he considered the word used to be "ordinary in speech as he learned it, English not being his native language."
"While the Stewards accept that this may be true, it is important for role models to learn to be mindful when speaking in public forums, in particular, when not under any particular pressure," they added.
"The Stewards note that significant fines have been levied for language offensive to or directed at specific groups. This is not the case here.
"But, as this topic has been raised before and is well known by the competitors, the Stewards determined to order a greater penalty than previously."
The work of public interest will be carried out in coordination with the FIA's secretary general for sport at a date to be decided.
Verstappen was describing the state of his car in qualifying for last weekend's Azerbaijan Grand Prix but the incident came after FIA president Mohammed Ben Sulayem had urged drivers to watch their language, comparing them to rappers.
Formula 1 drivers are heard over the team radio during the heat of battle by millions of viewers worldwide, with the swearing bleeped out.
"We're not rappers, you know," Ben Sulayem, an Emirati, told motorsport.com in an interview. "They say the F-word how many times per minute?"
Asked about Ben Sulayem's comment, Verstappen said everyone swore and suggested it was a losing battle.
"Even if a five-year-old or six-year-old is watching, I mean, they will eventually swear anyway," he said.
"Even if the parents won't, or they will not allow it, when they grow up they will walk around with their friends, and they will be swearing."
The FIA has long sought to curb swearing in press conferences and on air, with Ferrari boss Fred Vasseur and Mercedes' Toto Wolff warned last year for similar use of language at the Las Vegas Grand Prix.
