# Introduction to SAT II Physics

(Darren Dugan) #1

questions. Invariably, some of these answer choices will be tempting for some questions but not
for others. For instance, you can be pretty sure that kinetic energy isn’t measured in hertz: E may
be a tempting answer choice for other questions but not for that one, so you can eliminate it.
Another point that may help you guess in a pinch is that you’ll rarely find that the same answer
choice is correct for two different questions. The directions for classification questions explicitly
state that an answer choice “may be used once, more than once, or not at all,” but on the whole,
the ETS people shy away from the “more than once” possibility. This is by no means a sure bet,
but if you’re trying to eliminate answers, you might want to eliminate those choices that you’ve
already used on other questions in the same set.
If you’re wondering, the answers to the above questions are 1 A, 2 E, and 3 D.
“EXCEPT” Questions

``````All of the following are true about an -particle EXCEPT
(A)It has an atomic mass of 4
(B)It carries a positive charge
(C)It is identical to the nucleus of a helium atom
(D)It will always pass right through a thin sheet of gold foil
(E)It contains two neutrons``````

Questions of the “EXCEPT” variety contain a bunch of right answers and one wrong answer, and
it’s generally possible to spot one or two right answers. Even if you can’t answer the question
confidently, you might remember that alpha particles have a positive charge and that they are
identical to the nucleus of a helium atom. Already, you’ve eliminated two possible answers, and
can make a pretty good guess from there.
If you’re interested, the answer is D: Rutherford’s gold foil experiment showed that alpha particles
would occasionally deflect off the gold foil at extreme angles, thus proving that atoms have nuclei.
“I, II, and III” Questions

``````For which of the following is f > 0:
I. Concave mirror
II. Convex mirror
III. Converging lens
(A)I only
(B)II only
(C)I and III only
(D)II and III only
(E)I, II, and III``````

In this style of multiple-choice question, the “I, II, and III” questions provide you with three
possible answers, and the five answer choices list different combinations of those three. There’s an
upside and a downside to questions like these. Suppose you know that a concave mirror has f > 0
and a convex mirror doesn’t, but you’re not sure about a converging lens. The downside is that
you can’t get the right answer for sure. The upside is that you can eliminate B, D, and E, and have
a 50% chance of guessing the right answer. As long as you’re not afraid to guess—and you should
never be afraid to guess if you’ve eliminated an answer—these questions shouldn’t be daunting.
The value of f for a converging lens is positive, so the answer is C.