MCAT Physics Question — Electric Field
 by
 Sep 09, 2014
 MCAT Question of the Day
The distance from a point charge is tripled. What is the ratio of the strength of the electric field at the original distance to the strength of the field at the new distance?
a) 9:1
b) 3:1
c) 1:3
d) 1:9
Explanation
The strength of the electric field due to a point charge is given by the relationship: E=kq/r2. If E is the strength of the field at the original location, E’=kq/(3r)2=kq/(9r2). E’=E/9, i.e. E=9E’, and the ratio of the strength of the electric field at the original location to the strength at 3x the distance is 9:1.
a) 9:1, correct.
b) 3:1, incorrect, This would be true only if the E was inversely proportional to the distance, but E is inversely proportional to the distance squared.
c) 1:3, incorrect, This would be true if E was proportional to the distance, but E is inversely proportional to the distance squared.
d) 1:9, incorrect, This would only be true if E was proportional to the distance squared, but E is inversely proportional to the distance squared.
Want more MCAT practice?
We’ve got options for every schedule and learning style!
From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative fulllength practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!
Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT expert using the form below. No obligation, just expert advice.
Search the Blog
Free Consultation
Interested in our Online MCAT Course, OneonOne MCAT Tutoring or Med admissions packages? Set up a free consultation with one of our experienced Senior Student Advisors.
Schedule NowPopular Posts

MCAT Blog What's on the MCAT?

MCAT Blog How to Review MCAT Full Lengths
Free MCAT Practice Account
Need great MCAT practice?Get the most representative MCAT practice possible when you sign up for our free MCAT Account, which includes a halflength diagnostic exam and one of our fulllength MCAT practice exams.
Learn More