Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    3
    ReputationRep:
    When we work out specific charge, do we take the charge to be positive? In my textbook, it says that the specific charge of the electron is positive, which wouldn't be true if we used its charge to be  -1.6 \times 10^-19 , would it?

    Thanks


    Posted from TSR Mobile
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by AlphaNick)
    Yes, it's supposed to be negative, -1.60x10-19
    Why does the AQA book say that the specific charge of an electron is 1.76 x 10^11 then? I came to the assumption that the formula for specific charge was hence:

     specific charge = | \frac{charge}{mass} | ?


    Posted from TSR Mobile
    Offline

    10
    It can be expressed as either positive or negative. Look through various books and sources and you will find both.
    In many cases the sign of the charge is not important. What is important is the magnitude of the ratio.
    If you see the specific charge of an electron quoted as 1.76 x 1011Ckg-1 then there is no need to worry about it. You know the charge is negative and the value quoted is just the magnitude of the ratio. If in doubt, when you give the value, put the minus sign in.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by AlphaNick)
    because it's wrong, the electron's specific charge is -1.76x1011 C kg-1
    Yeah, I agree. I don't like the fact that AQA are explicitly telling incorrect things. They should at least say: 'the magnitude of the specific charge of an electron is...'


    Posted from TSR Mobile
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?

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

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