Doing well on the Physics SAT Subject Test requires two things: a thorough knowledge of the material covered on the test and the knowledge of how to take the test. Since the exam is much too long for even high school physics savants to finish, in order to do well, it’s important to know how to approach the test so as to maximize your time and maximize your score. Here I share the most important test-taking strategies that will allow you to do well on the Physics SAT Subject Test.
1. Don’t do the questions in order
The questions on the Physics SAT are not organized in order of difficulty. That is, the easy questions are not at the beginning of the exam, and the hard ones are not at the end. However, if you do the questions in order, there might be easy questions at the end that you miss entirely because you ran out of time!
To avoid this, answer questions in accordance with your own personal order of difficulty. When you receive your booklet (or when you’re doing practice exams), first quickly skim all of the questions and immediately answer the ones that are very easy for you. Next, take a second pass through the exam, answering questions that require a little bit more time. This strategy makes sure that you actually get to answer every question that you can answer.
The personal order of difficulty will vary widely from person to person, and you need to find your own difficulty by taking a diagnostic test. For example, one student may be strongest in mechanics because that’s the most recent class that they took. Another student may not be able to answer any mechanics problems at all, but will be able to get every electromagnetism question. In other words: level of difficulty is based on the individual test taker, not on some universal standard.
Taking a diagnostic test will allow you to identify your areas of strength and weakness. This is also one area where a tutor would be able to help. Tutors are trained to find where students need help and guide them to increase their skills in those areas.
2. If two answers are equivalent, both of them are wrong
There is only one right answer for any given problem on the Physics SAT. Use this to your advantage! If you stumble upon a question where two answer choices are equivalent, feel free to eliminate them both, since both of them can’t be correct. For example, consider the following problem:
This problem is asking you to determine which axis of length appears to change when two objects are traveling close to the speed of light. In this problem, the body parts of the robot are not so much important as the axes that they exist on. Put yourself in the position of one of the robots (doesn’t matter which one). If moving in this manner close to the speed of light would make you observe the other robot as taller, would not the length of the other robot’s legs also change? That means both of these answers are wrong. Similarly, if moving in this manner changed the width of the robot’s body (which included the shoulders), would not the width of the robots faces also change width? That means these two answer choices are wrong as well! The last option (B) is the only one that doesn’t have an equivalent among the answer choices, so it must be the correct one.
3. Know when to skip
Unlike on the regular SAT, there is still a guessing penalty on the SAT Subject Tests. Specifically on the physics exam, a wrong answer is given -1/4 of a point, while a no answer gives 0 points – neither adding nor taking away. Plus, the exam is much too long for anyone to answer all the questions and, if you get all the other answers correct, you can leave up to fifteen questions unanswered and still get a perfect score! Building a skipping versus guessing strategy is in your best interest, not only to save time but also to increase your score. So: when should you guess and when should you skip?
As an exercise purely in odds, consider your average gain from guessing when you have 5,4,3,or 2 answer choices to choose from. If you have five answer choices, there are four wrong ones, which will lead you to a penalty of -1/4 each, and one correct answer, which will lead you to a point gain of +1. So on average, the number of points you would gain if you guessed every time would be:
(4)*(-1/4) + (1)*(1) = 0
There would be no gain, so it’s not in your favor to guess for every question. Now imagine you could eliminate one definitely wrong answer and you would guess among the others. Now you only have three incorrect answers and one wrong answer:
(3)*(-1/4) + (1)*(1) = 0.25
Now the average gain is positive and there is an (average) benefit to guessing! Similarly, if you can eliminate two wrong answers, there is an average gain of 0.5, and if you can eliminate three, there is an average gain of 0.75.
You may or may not be a gambling person. 0.25 average gain may not be enough to entice you. But the general rule is that you should not guess when you cannot eliminate any answers. From there, it’s up to you.
4. If part of an answer is wrong, the whole answer is wrong
Process of elimination is your best friend for this exam. If part of an answer choice is incorrect, you can eliminate that whole answer choice. For example, consider the following problem:
For this problem, you need to remember that the speed of a satellite in orbit around a mass M, a distance r away from the mass’s center is given by
where G is the gravitational constant. Both of the satellites orbit the same mass, so M is the same for the calculation for both satellites. Since the speed is inversely proportional to the distance, we know that the one further away will be slower. We haven’t done any math yet, and we can already eliminate answer choices C and D! From there, it’s plugging in 2r and r to the equation and seeing that satellite 1 will be fast by a factor of root 2 (A).
5. Bubble in your answers in groups
This may seem rather silly, but transferring your answers from your booklet to the answer sheet after each question takes a lot of time. You are much faster at transferring answers when you do more than one at a time. As you go along taking the test, circle your answer choices in the booklet. Then, once you’ve answered 10-15 in a row, transfer them all together to the answer sheet. This strategy can save you up to two minutes on the exam. When you have less than a minute per question, this extra time is precious!
If you would like more strategies and tips on how to prepare and take the SAT Subject Test in Physics, reach out to a Cambridge Coaching tutor today!
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