A-Level Physics - [Question]

    • Thread Starter
    Offline

    3
    ReputationRep:
    How many electrons flow past a point each second in a 5.0mA electron beam?
    I used I=Q/T
    I = 0.005 A
    Q =
    T = 1
    so Q = 0.005 C
    right?
    Offline

    2
    ReputationRep:
    That seems correct.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by JustasB)
    That seems correct.
    I got the answer it was just telling me it was wrong as I had
    3.13 instead of 3.1

    Thanks
    Offline

    2
    ReputationRep:
    (Original post by AdeptDz)
    I got the answer it was just telling me it was wrong as I had
    3.13 instead of 3.1

    Thanks
    The answer was to 2 significant figures, so the answer of 3.13 is correct but it should be rounded to the correct number of significant figures.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by JustasB)
    The answer was to 2 significant figures, so the answer of 3.13 is correct but it should be rounded to the correct number of significant figures.
    Thanks
    Do you have an idea on this question:
    Alpha particles have twice the charge of an electron. What is the current caused by a radioactive source which emits 3000 alpha particles per second, to 3 significant figures?

    First I found out the charge which is 3.2*10^-19 (For one alpha particle) then I multiplied it by 3000 to get charge for 3000 alpha particles which is 9.6x10^-16 C now i used I = Q/T
    so I would equal 9.6 x 10^-16 aswell but i'm not sure what to do now or what i done wrong as this answer is incorrect
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by AdeptDz)
    Thanks
    Do you have an idea on this question:
    Alpha particles have twice the charge of an electron. What is the current caused by a radioactive source which emits 3000 alpha particles per second, to 3 significant figures?

    First I found out the charge which is 3.2*10^-19 (For one alpha particle) then I multiplied it by 3000 to get charge for 3000 alpha particles which is 9.6x10^-16 C now i used I = Q/T
    so I would equal 9.6 x 10^-16 aswell but i'm not sure what to do now or what i done wrong as this answer is incorrect
    oh wow, it is correct just not to 3 sig. fig. once again.
    Keep making the same mistake, my bad!

    Edit:
    Do you know if i have to always use correct sig. fig. in the exam? (AQA if it helps)
    Offline

    2
    ReputationRep:
    (Original post by AdeptDz)
    oh wow, it is correct just not to 3 sig. fig. once again.
    Keep making the same mistake, my bad!

    Edit:
    Do you know if i have to always use correct sig. fig. in the exam? (AQA if it helps)
    Use the same number of significant figures as given in the question.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by JustasB)
    Use the same number of significant figures as given in the question.
    okay thanks
    Offline

    1
    ReputationRep:
    Did you get these questions on Isaac physics because I have been set this board and I literally have no clue! Hell
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Mossie99)
    Did you get these questions on Isaac physics because I have been set this board and I literally have no clue! Hell
    Ye I did ; was a while back though


    Posted from TSR Mobile
    Offline

    1
    ReputationRep:
    (Original post by AdeptDz)
    Ye I did ; was a while back though


    Posted from TSR Mobile
    Found out I was doing the same mistake as you with my sig figs! Gets very frustrating when it continuously says incorrect! Thanks anyway
 
 
 
Write a reply… Reply
Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: November 15, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Today on TSR
Poll
Would you prefer to be told about sex by your:
Help with your A-levels

All the essentials

The adventure begins mug

Student life: what to expect

What it's really like going to uni

Rosette

Essay expert

Learn to write like a pro with our ultimate essay guide.

Uni match

Uni match

Our tool will help you find the perfect course for you

Study planner

Create a study plan

Get your head around what you need to do and when with the study planner tool.

Study planner

Resources by subject

Everything from mind maps to class notes.

Hands typing

Degrees without fees

Discover more about degree-level apprenticeships.

A student doing homework

Study tips from A* students

Students who got top grades in their A-levels share their secrets

Study help links and info

Can you help? Study help unanswered threadsRules and posting guidelines

Sponsored content:

HEAR

HEAR

Find out how a Higher Education Achievement Report can help you prove your achievements.

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.