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The letter, addressed to Larry Page, Google’s chief executive, outlined eight questions for Google and asked for a response by June 14.

“We are curious whether this new technology could infringe on the privacy of the average American,” the letter said. “Because Google Glass has not yet been released and we are uncertain of Google’s plans to incorporate privacy protections into the device, there are still a number of unanswered questions.”

The glasses, which are not yet for sale to the public, connect to the Internet and allow people to do things like take photographs, record and watch video, send text messages, post to social media sites and read text snippets. They have already raised privacy concerns on issues like unwanted recording.

The request, from the Bipartisan Congressional Privacy Caucus, came as Google held its annual I/O developers conference in San Francisco, where it showed off Glass, gave software developers information about how to build apps for the device and introduced seven new apps, including ones from Facebook, Twitter and CNN.

The group, for which Representative Joe Barton, Republican of Texas, is a co-chairman, asked questions including how Google would collect and store data from the devices, how it would ensure that it did not unintentionally collect private data, how Google would protect the privacy of people not using Glass when they are with people using it and whether the device would have facial recognition technology.

Steve Lee, director of product management for Google Glass, addressed the facial recognition question in a statement.

“We’ve consistently said that we won’t add new face recognition features to our services unless we have strong privacy protections in place,” he said.

Google has faced punishments over privacy violations with past products, including a settlement with the Federal Trade Commission over a social networking tool and another one with 38 states over data collection during its Street View mapping project.

In a session at the conference, Mr. Lee addressed other concerns in the letter. Google followed all its privacy and data collection policies with Glass, he said, and built social cues into the device to help prevent certain privacy violations. For instance, users have to press a button or speak to Glass to take a photograph or record video, and look directly at whatever they are shooting.

Still, one developer said he had already built an app for Glass that enables users to take a photograph with a wink.

In a statement, Chris Dale, a Google spokesman, said, “We are thinking very carefully about how we design Glass because new technology always raises new issues.”

He added that Google was slowly selling early versions of the device, which cost $1,500, to people who sign up for them, “to ensure that our users become active participants in shaping the future of this technology.”