Question

Quantum mechanics asserts that the position of the electron can only be known in terms of probabilities and its motion (path) cannot be known at all, whereas classical mechanics asserts that the position and motion of any particle can be determined exactly.
True
False

Answer 1

There's one false statement, so the whole thing must be false.

Answer 2

I agree with JFraser, one false statement makes the whole statement false.

Answer 3

Tricky. There's some chance that the answer desired is "True" because the first part of the statement is true *IF* you include the condition that the electron is in a stationary bound state, e.g. known to be in the 1s orbital of an H atom, known to be in the ground state of a harmonic potential, et cetera. Under those conditions, it is indeed impossible to predict precisely the position of an electron, and one can only speak of the probabilities of it being at various positions.

However, in the general case, it is certainly possible to know the position of an electron as precisely as you wish -- provided you give up knowledge of the observables that fail to commute with position, like momentum.

The statement that the path cannot be known at all is overstated. If nothing else, one can certainly know it to a perfectly acceptable level of macroscopic precision -- this is why we can speak of an electron beam, for example. However, it is certainy true that the path cannot be specified EXACTLY, because that would necessarily involve simultaneous measurement of the position and velocity, which don't commute.

One would need to know more context for this question to know whether it was carefully written, and therefore the answer is "false," or whether it was carelessly written, and therefore the answer might be "true."

Answer 4

@Carl_Pham says it exactly as I would have, had I had the time before teaching to do so ;-)