The answer depends on where the employer wants to put the cameras and why. The employer must have a reasonable, legitimate business reason for monitoring employees in this manner (for example, to discourage theft from a cash register or to enhance the security of customers and employees). And some states have made certain areas of the workplace (for example, the bathroom and changing areas) off-limits to this type of monitoring.
Even with a legitimate reason, your employer must inform you and your coworkers that the cameras are there. Also, some states prohibit the use of certain types of surveillance devices, such as one-way mirrors.
For more information on workplace surveillance, see Nolo's article Cameras and Video Surveillance in the Workplace.
Psychological tests given by employers are often invasive and their purpose questionable. If the employer doesn't seem to have a sound reason for giving the test, and the questions make you uncomfortable, then you might have a legitimate claim that the employer is violating your privacy rights.
For more information on whether employee testing is allowed, see Nolo's article Workplace Testing: What Your Employer May Require.
Almost certainly, the answer is yes. If your employer has a policy saying that its computer and email systems should be used for business purposes only, and/or warning employees that it has the right to monitor all messages sent on its equipment, then it has the right to monitor your work email. If it has policies that lead you to believe your email is private, then its rights may be more limited. As a practical matter, however, almost every court to consider email privacy claims have found in favor of the employer's right to monitor, regardless of its policies.
For more information on email privacy, see Nolo's article Email Monitoring: Can Your Employer Read Your Messages?
Not if you work for a private employer. Like the rest of the federal Constitution, the First Amendment protects all of us from the government, not from private companies. While the First Amendment prohibits the government from telling us what we can say (within reason), it doesn't apply to private employers.
However, other laws may protect bloggers and posters from employer discipline, depending on the subject matter of your posts. For more information, see Nolo's article Fired for Blogging.
The law regarding medical marijuana is still developing, but so far it looks like employees can be fired for marijuana use, even if they have a legally valid prescription for the drug and don't use it at work. Medical marijuana is legal in more than a dozen states, with written authorization from a doctor. However, this protects you only from criminal prosecution under state drug laws: It doesn't protect you from federal drug laws, nor does it protect you from discipline or termination under your employer's policies. Courts in at least two states that recognize medical marijuana, California and Oregon, have ruled against an employee in this situation.
For more information on how much employers may inquire about, or consider, what you do in your own time, see Nolo's article Off-Duty Conduct and Employee Rights.
It depends on your state's law and your employer's policies. Many states give employees the right to view their personnel files, although there may be documents you aren't entitled to see (such as reports from criminal investigations or reference letters). Some states give employees a right to a copy of at least some of their personnel documents, such as documents they have signed. And even if state law doesn't give you these rights, your employer's policies may allow you to view or copy your file.
For more information, see Nolo's article Your Personnel File and Your Rights.
The answer depends on your employer's policies and reason for searching. When courts evaluate workplace privacy claims, they balance the employer's legitimate justification for intruding against the employee's reasonable expectation of privacy. If something of great value to the company has been stolen that day, and the employer decides to search all employees in a reasonable way (for example, searching their bags, not their bodies), then your employer has a pretty good reason to search. Particularly if your employer has a written policy warning employees that they might be subject to search, which diminishes employees' expectations of privacy, this type of search might be legal. However, an employer who does this as a daily routine, targets you specifically without a good reason, or searches more intrusively, will be on shakier legal ground. This is especially so if the employer has no policy on searches and has not conducted searches in the past, which makes your reasonable expectations of privacy stronger.
For more on how courts evaluate workplace privacy claims, see Nolo's article Proving Your Privacy Was Violated at Work.