electromagnetic induction - 2025 ACF Fall

Tossup

David Griffiths claims that there are really two laws of this process and that only relativity explains the equivalence between a central quantity and its “motional” form. (-5[1])In a common demonstration of this (-5[1])process, a magnet dropped through (10[1])a copper tube falls (10[1]-5[1])unexpectedly (10[4]-5[3])slowly. (10[14]-5[8])This (10[1])process is governed (10[1]-5[2])by (10[2])the equation (10[1])“del cross (10[1])E (10[5])equals minus (10[2])dB/dt,” (10[3]-5[1])which (10[1])implies (10[1])that the negative (-5[1])time derivative of magnetic flux (10[1])equals (10[1]-5[1])the (-5[1])emf (10[6]0[1]-5[3])(“E-M-F”). This (10[1])process (10[1])creates eddy currents (10[2]-5[1])that rapidly (10[4]-5[1])heat (10[1])metal in a namesake type of (-5[1])cooktop. (10[13]-5[2])Lenz’s (10[6])Law (10[9])explains (10[4]-5[1])the (-5[1])negative (-5[1])sign in Faraday’s (10[1])law (10[1])of this process. (10[2])For 10 points, (0[1])name this process in which a changing magnetic field creates (-5[1])an electric (10[1])field. (10[2])■END■ (10[20]0[10])

ANSWER: electromagnetic induction [accept Faraday’s law of induction; prompt on eddy currents before “eddy” is read by asking, “what process causes them?”]

<Editors, Physics>

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Buzzes

Player	Team	Opponent	Position	Value
Taman Truong	USC B	UCLA A	26	-5
Daniel Abrams	Rutgers B	Lehigh A	32	-5
Andrew Nucci	UCLA B	Claremont B	37	10
Advai Srinivasan	UC Irvine	Claremont C	41	10
March Delfin	UCSD A	UCSD B	41	-5
Aaryan Sumesh	Berkeley Archer Queen	Berkeley Mighty Miner	42	10
Kevin Cronk	Virginia Tech C	UNC D	42	-5
Dustin Sanders	Chicago B	Purdue A	42	-5
Drew Wetterlind	Iowa State	Wisconsin A	42	-5
Surya Dinesh	MIT A	Brown B	42	10
James Haddix	Washington State	British Columbia C	42	10
Michael Shipman	Cambridge D	Imperial A	42	10
Danny Han	Stanford B	Berkeley Boss Bandit	43	10
Winston Zuo	UC Santa Barbara	UCLA C	43	-5
Denali Tran-Le	McGill B	Ottawa D	43	-5
Simon Choist	Queen's A	Brock A	43	-5
Carter Yott	McMaster A	Toronto D	43	-5
Peter Zeng	Ohio State A	Louisville B	43	10
Oliver Thompson	CWRU D	Michigan C	43	-5
Nate Brown	CWRU C	Michigan D	43	10
Xavier Bornhorst	Maryland A	Rutgers A	43	10
Vedh Ramesh	Penn	Rutgers D	43	10
Aarnav Vyas	Illinois Orange	Indiana B	43	10
Brian Qian	Illinois Canada	Purdue B	43	10
Liam Buck	St. Thomas	Macalester	43	10
Suyog Vibhuti	Washington Steelhead	Washington Chinook	43	10
Daniel Lu	Washington Pink	Washington Masu	43	10
Jackson McDonald	Alabama A	Vanderbilt A	43	10
Shaya Farahmand	Georgia Tech B	Auburn B	43	-5
Tal Bowen	Durham A	Edinburgh C	43	10
Ahmed Azhari	Cambridge E	Cambridge C	43	10
Eli O'Sick Johnson	Binghamton C	Rochester	43	-5
Eli O'Sick Johnson	Binghamton C	Rochester	43	-5
Aaron Wang	Cornell A	Cornell D	43	10
Ollie Glin-Conway	Imperial D	Oxford	44	10
Chris Chang	USC A	UCLA E	47	-5
Luke Sauer	Michigan Tech	Wisconsin C	47	-5
Salil Jain	Williams B	Dartmouth B	47	10
Annika Larson	Claremont A	UCLA D	48	10
Charlie Ruff	McGill A	McGill C	48	10
Nishad Joshi	Kentucky	Pittsburgh	50	10
Luke Simon	Alberta B	Washington Chum	52	10
Jason Thieu	Michigan State A	Louisville A	53	10
Henry Ding	Princeton	Columbia A	53	10
Anurag Shah	Indiana A	WashU Grolars	53	10
Daniel Chen	Emory A	Georgia A	53	10
Charlotte Nicholas	Durham B	Edinburgh B	53	10
Pace Klein	CWRU B	CWRU A	55	10
Jiping Fang	Illinois Blue	William Woods University A	55	10
Nathan Redford	Liberty A	William & Mary C	56	-5
Kelvin Ni	NYU A	Maryland C	56	10
Eames Weeks	Brown A	Dartmouth A	56	10
Abhinav Dinesh	LSE	Warwick	56	10
Bharath Ram	Georgia Tech A	Georgia Tech C	57	10
Wesley Stine	Clemson A	Chipola College	58	10
Ryan Gomes	Florida Tech A	Florida B	61	-5
Caleb Slusher	South Carolina A	Tennessee A	66	10
Artem Vovchenko	Ohio State C	Louisville D	67	10
Cy Stavros	Vermont A	Tufts B	67	-5
Sicheng Jiang	Toronto H	Toronto I	68	-5
David Yuan	Berkeley Little Prince	Berkeley Skeleton King	69	10
Joseph Wang	UCLA E	USC A	69	0
Adrian O'Leary	Waterloo A	Toronto A	69	-5
Gavin Ge	Waterloo B	Toronto G	69	10
Liam Rojas	Virginia A	Virginia Tech B	69	10
Misty Chen	Purdue C	Iowa A	69	10
Rafael Gómez	Amherst B	Boston University B	69	10
Jack Disbury	Durham D	Edinburgh D	69	-5
Danny Cutbill	RIT A	ESF	69	10
Peter Smith	Binghamton A	RIT B	69	-5
Rafa Travis	Durham C	Sheffield B	70	10
Nathan Woolery	Louisville C	Michigan State D	71	10
Rohit Chintala	Maryland B	George Mason A	74	10
Sonali Srikanth	Georgia Tech D	Tennessee B	74	10
Mata Cooper	Southampton	Cambridge A	74	-5
Ethen Sun	Toronto C	Toronto B	76	10
Peyton Legg	UCF A	Florida A	76	-5
Aryan Malhotra	Rutgers C	NYU C	76	10
Matthew Kohn	Williams A	Vermont B	76	10
Shivam Saxena	Georgia Tech F	Georgia Tech E	76	10
Jesse Mindel	NCSU A	William & Mary A	77	10
Abhay Ariyapappillil	Ottawa B	Ottawa A	83	-5
Justin Sato	Stanford A	UCSC	84	-5
Gus Morin-Strom	Carleton B	Ottawa C	84	10
Adithya Parat	McMaster C	Toronto F	84	10
Lucas Hall	Waterloo C	McMaster B	84	10
Taran Knutson	Michigan A	Michigan B	84	10
Parker Jones	NCSU B	Liberty B	84	-5
Fuller Wray	Virginia Tech A	UNC A	84	10
Eric Morshed	Johns Hopkins	George Mason B	84	10
David Black	Illinois Champaign	Iowa B	84	10
Vivian Lu	Wisconsin C	Michigan Tech	84	10
Andrew Park	Harvard	Brandeis Beethoven	84	10
Doug Frederick	Auburn A	Tennessee Tech	84	10
John Shelley	Clemson B	Montevallo	84	10
Vishrut Pisupati	Imperial B	Birmingham	84	10
Ariyan Miah	Binghamton B	Cornell C	84	10
Juan Landaeta	Florida State A	ERAU Daytona A	85	10
Ryan Liu	Ohio State D	Michigan State C	85	10
Sam Kung	UNC C	UNC B	85	10
Andrew Sklar	Vassar B	Rowan	85	10
Madeline Strauss	Tufts A	Amherst A	85	10
Laura Bullock	Sheffield A	Edinburgh A	85	10
Nick Machin	UCLA A	USC B	86	10
Platon Gorokhov	Toronto E	Guelph A	86	10
Miles Phillips	Florida Tech B	South Florida A	86	10
Lily Katz	Stony Brook	Vassar A	86	10
Saswat Sasha Tripathi	Chicago A	WashU Grizzlers	86	10
Duncan Occhiogrosso	UConn A	Boston University A	86	10
Lola Maas	Washington Coho	British Columbia A	86	10
Brayden Zhang	Vanderbilt B	Mississippi State A	86	10
Josh Morris	Bristol	Imperial C	86	10
Alden Thompson	Carleton A	McGill E	87	-5
Magnolia Schnirman Barría	NYU B	Lehigh B	87	10
Shining Sun	Boston College A	Brandeis Mozart	87	10
Eleanor Arron	Williams C	Dartmouth C	87	10
Deeksha Easwar	Washington Sockeye	Arizona State A	87	10
Kevin Liu	Texas	British Columbia B	88	-5
Caleigh Greene	Tusculum A	Liberty C	89	-5
Austin Tran	Rose-Hulman A	Purdue D	92	10
Anne Fjeld	Alberta A	Washington Atlantic	93	10
Kieran Freed	Rochester	Binghamton C	96	10
Kieran Freed	Rochester	Binghamton C	96	10
Noah Scattergood	Brock A	Queen's A	99	0
Josue Lopez	WVU A	WVU B	109	-5
Joyann Hua	British Columbia B	Texas	111	10
Saju Ramraj	Toronto I	Toronto H	112	10
Matthew Westley	Purdue A	Chicago B	112	10
Lorie Au-Yeung	UCSC	Stanford A	113	10
Ishan Pachauri	UCLA C	UC Santa Barbara	113	10
Ethan Ririe	UCSD B	UCSD A	113	10
Valentina Chamandy	McGill E	Carleton A	113	10
Tristan Scarlett	Ottawa D	McGill B	113	10
Rebecca Li	Ottawa A	Ottawa B	113	10
James Xiao	Toronto A	Waterloo A	113	10
Will Marcotte	Toronto D	McMaster A	113	10
June Miller	Florida A	UCF A	113	10
Reed Sexton	Michigan C	CWRU D	113	10
Emmet Ewing	Michigan State B	Ohio State B	113	10
Venkat Das	WVU B	WVU A	113	0
Jaden Rupolo	Liberty B	NCSU B	113	0
Justine Hopkins	Liberty C	Tusculum A	113	0
Noah Fine	UNC D	Virginia Tech C	113	10
Sophia Jagels	William & Mary B	JMU A	113	0
Mason Lambert	JMU A	William & Mary B	113	0
Jacob Schildkraut	William & Mary C	Liberty A	113	0
Brayden Whitlow	George Mason C	Columbia B	113	10
Zachary Fitzpatrick	Wisconsin B	Minnesota	113	0
Alex Feller	Minnesota	Wisconsin B	113	10
Will Huang	Wisconsin A	Iowa State	113	10
Reid Eichberg	Tufts B	Vermont A	113	10
Edward Zhang	Vanderbilt C	Auburn C	113	0
Jason Cottle	Clemson C	Sewanne	113	0
Nelson Adams-Riley	Sewanne	Clemson C	113	0
Brandon Hunt	Auburn B	Georgia Tech B	113	10
Lucy Izabella	Edinburgh D	Durham D	113	10
Antara Bhattacharya	Cambridge A	Southampton	113	10
Jake Scoville	RIT B	Binghamton A	113	10

Summary

Tournament	Edition	TUH	Conv. %	Neg %	Average Buzz
UK (North)	UK	5	100%	20%	72.80
UK (South)	UK	7	100%	14%	66.86
Northern California	US	4	100%	25%	66.75
Southern California	US	7	86%	57%	73.00
Eastern Canada (1)	US	5	100%	60%	94.20
Eastern Canada (2)	US	9	89%	44%	92.13
Florida	US	4	75%	50%	94.67
Great Lakes	US	12	92%	17%	70.64
Lower Mid-Atlantic	US	9	56%	44%	85.60
Upper Mid-Atlantic	US	10	100%	0%	72.60
Upper Mid-Atlantic	US	2	50%	50%	74.00
Midwest	US	9	100%	11%	70.78
North	US	4	100%	50%	88.25
Northeast	US	11	100%	9%	75.64
Pacific	US	8	100%	13%	69.63
Southeast	US	13	85%	8%	72.18
Upstate NY	US	6	100%	50%	83.50