1. Photo-electric effect (one black box) During the last Wednesday (1/27) lab session, potentially one student turned the dial, forced it passing the limit and jammed the spring-loaded set-up inside. Luckily, Prof. Crowell was around and fixed the system immediately. Now an additional note has been posted on the top of the “black box”. The backlash of a dial.

2. Photo-electric effect In During the last Wednesday (1/27) lab session, potentially one student turned the dial, forced it passing the limit and jammed the spring-loaded set-up inside. Luckily, Prof. Crowell was around and fixed the system immediately. Now an additional note has been posted on the top of the “black box”.

3. Doug Osheroff’s notebook (4/20/1972) Importance of lab notebook, published by National Science Foundation The Nobel Prize in Physics 1996 David LeeDavid Lee, Douglas Osheroff and Robert RichardsonDouglas OsheroffRobert Richardson "for their discovery of superfluidity in helium-3"

4. Non-linear Kerr rotation vs. Temperature: Sr 2 IrO 4 L. Y. Zhao et al., Nature Phys 12, 32 (2015).

5. Basic concepts of circuits You learned various circuits in parallel (P) and series (S) in 1*02 labs. The proper ways to connect various instruments into a circuit are discussed in 1*02-lecture. Question: 1) An ammeter should be connected to the circuit in P or S? How about 2) a voltmeter? 3) an ohmmeter? 4) a constant current source? Now in this lab, there is a real test of your knowledge about simple circuits. Please write down the answers in your paper. Four students have been picked to write their answers on the white board.

6. Meaning of significant figures In conducting the lab # 10, the following information is acquired: We obtained 10 counts in one measurement and an average of 10. counts after carrying out measurements 10 times. There are four 10’s in this statement. Do they have the same meaning?

7. Meaning of significant figures In conducting the lab # 10, the following information is acquired: We obtained 10 counts in one measurement and an average of 10.2 counts after carrying out measurements 10 times. Data: 10, 8, 11, 7, 9, 12, 14, 10, 9, 12. Intrinsically, there exists randomness in the acquired data. In addition to errors in the multimeters, this is another possible source of errors. How to obtain the error-bar from this set of data?

8. Root-mean-square Data: 10, 8, 11, 7, 9, 12, 14, 10, 9, 12. 1.List the data in an excel sheet. 2.Obtain the average = sum(all counts)/No. 3.Square of deviation = (count-average)^2 4.Root-mean-square =[Avg (Square of dev)]^(1/2) 5.Format cell/number/decimal places (1) 1 2 3 4 5

9. Questions: I. How many significant digits are there in the following numbers? a) 0.0048; b) 976.45; c) 185,000; d) 5.000 II. What is the most significant digit in each of the numbers of question #1. Please write down the answers in your paper. Four students have been picked to write their answers on the white board.

10. Questions: I. How many significant digits are there in the following numbers? a) 0.0048; b) 976.45; c) 185,000; d) 5.000 II.. III. Round each number in question #1 to two significant digits. IV. Scientifically, what are the best ways to present those numbers? Please write down the answers in your paper. Four students have been picked to write their answers on the white board.

11. Answers: I. How many significant digits are there in the following numbers? a) 0.0048; b) 976.45; c) 185,000; d) 5.000 a) 2; b) 5; c) 3; d) 4 II. What is the most significant digit in each of the numbers of problem #1. a) 4; b) 9; c) 1; d) 5 III. Round each number in problem #1 to two significant digits. a) 0.0048; b) 980; c) 190,000; d) 5.0 IV. Scientifically, what are the best ways to present those numbers? a) 4.8 x 10 -3 ; b) 9.7645 x 10 2 ; c) 1.85 x 10 2 ; d) 5.000