MYTUTOR SUBJECT ANSWERS

358 views

How to i calculate total resistance in a circuit?

Total resistance in a circuit depends on whether the resistors are in series or parallel since this determines which equation is to be used.

In series, resistors are essentially lined up next to each other so the total is simple since it is just the sum of the resistors resistance in ohms.

e.g. if a circuit has one 10ohm, one 45ohm and one 235ohm resistor in it, all three of which are in series, the total resistance is (10+45+235)ohm = 290ohms

In parallel each resistor is on its own path for the electricity to follow and as a result the equation is not quite the same, we use the equation:

 1/Rtotal = 1/R1 + 1/R+ 1/R..etc

e.g. a circuit has 3 resistors all in parallel. Their resistances are 25ohm, 5ohm and 100ohm respectivley, what is the total resistance of the circuit?

1/Rt = 1/25 + 1/5 + 1/100

1/R= 4/100 + 20/100 + 1/100

1/R= 25/100

100 = 25Rt

R= 4ohms

often the answer will be a fraction when calculating a parallel due to the fractions involved in the total calculation however i used a simpler calculation for the example to demonstrate the equation's use

Matthew K. GCSE Maths tutor, GCSE Physics tutor

1 year ago

Answered by Matthew, a GCSE Physics tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist

102 SUBJECT SPECIALISTS

£18 /hr

Eden H.

Degree: Engineering Science (Masters) - Oxford, Somerville College University

Subjects offered: Physics, Maths+ 1 more

Physics
Maths
Further Mathematics

“Hi, I'm Eden, a fourth year engineering student at the University of Oxford. When I was taking my GCSEs my Maths teacher showed me how maths is the language we use to describe our reality, and ever since then I've been impassioned to ...”

£18 /hr

Nishit B.

Degree: Engineering (Masters) - Oxford, New College University

Subjects offered: Physics, Maths+ 1 more

Physics
Maths
-Personal Statements-

“I am a second year Engineering undergraduate at the University of Oxford. I am happy to help with A-level/GCSE Maths.”

MyTutor guarantee

£18 /hr

Jan K.

Degree: Mathematics and Music (Bachelors) - Edinburgh University

Subjects offered: Physics, Maths

Physics
Maths

“About Myself I am a Mathematics student at Edinburgh University. I have a real passion for Mathematics, and I thouroughly enjoy explaining mathematical concepts to others. Having been home-educated all through school (which also gave ...”

MyTutor guarantee

About the author

£22 /hr

Matthew K.

Degree: General Engineering (Masters) - Warwick University

Subjects offered: Physics, Maths

Physics
Maths

“About MeI am a student studying a general engineering masters degree at Warwick University. I amfun and friendly and have a passion for maths and physics with a little bit of rugby on the side.I helped my brother whilst he was ...”

You may also like...

Posts by Matthew

How do I find the coordinates of maximum and minimum turning points of a cubic equation?

How do i solve simultaneous equations?

How to i calculate total resistance in a circuit?

Other GCSE Physics questions

What are some key differences between sound and light waves?

What is teminal velocity?

How can an object accelerate without changing speed?

How do fossil fuel powered power stations and solar powered power stations generates electricity?

View GCSE Physics tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok