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Physics question

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  • 31-03-2013 9:45pm
    #1
    HPMS
    Registered Users Posts: 141 ✭✭


    This is an old mock question on static electricity from a few years ago and it has me completely stumped. There's a diagram but don't know how to post photos so I'll describe it!

    Two positive point charges, each of 1.2 μC are situated
    at the vertices A and C of a right-angled isosceles triangle as shown. Calculate the total electric field intensity at B given that│AB│=│BC│= 40 cm. A (Permittivity of free space, Єo = 8.910–12 Fm–1)

    Diagram: Triangle ABC where AC is the hypotenuse and B is at the right angle!

    I appreciate any help! :)


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    #2
    decisions
    Closed Accounts Posts: 8,207 ✭✭✭decisions


    I could be totally wrong on this, but this is what I think it would be.


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    #3
    decisions
    Closed Accounts Posts: 8,207 ✭✭✭decisions


    Not attaching for me.

    Edit: got it to attach, I would embedd it but its showing huge on my tablet.


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    #4
    HPMS
    Registered Users Posts: 141 ✭✭HPMS


    That's the answer! Thanks so much! I have a crap teacher so I don't really understand how you knew which direction the vectors go in? I'd appreciate it if you could help me! :)


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    #5
    decisions
    Closed Accounts Posts: 8,207 ✭✭✭decisions


    No problem.

    I'll give you a hand if you could send me the mock paper your doing? Or any others you may have?


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    #6
    HPMS
    Registered Users Posts: 141 ✭✭HPMS


    decisions wrote: »
    No problem.

    I'll give you a hand if you could send me the mock paper your doing? Or any others you may have?

    Yeah sure, I'll send it to you in a PM. Give me a minute! :)


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    #7
    Leaving Cert Student
    Registered Users Posts: 1,026 ✭✭✭Leaving Cert Student


    Could you send it my way too mate? Would appreciate it!


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    #8
    Undeadfred
    Registered Users Posts: 301 ✭✭Undeadfred


    I was wondering if anyone hear could tell me how to charge an electroscope negatively?


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    #9
    Kingkumar
    Registered Users Posts: 59 ✭✭Kingkumar


    Bring a positively charged rod near the cap of the electroscope ( perspex rod rubbed with a woolen cloth) . The negative charges will be attracted towards the rod and so the cap would become negatively charged. Touch the cap with a metal conductor - the positive charge will run to earth while the negative will be held in place by the positively charged rod. Then remove the rod and voila - the negative charges will re-distribute themselves and the electroscope will become negatively charged.


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    #10
    Undeadfred
    Registered Users Posts: 301 ✭✭Undeadfred


    Kingkumar wrote: »
    Bring a positively charged rod near the cap of the electroscope ( perspex rod rubbed with a woolen cloth) . The negative charges will be attracted towards the rod and so the cap would become negatively charged. Touch the cap with a metal conductor - the positive charge will run to earth while the negative will be held in place by the positively charged rod. Then remove the rod and voila - the negative charges will re-distribute themselves and the electroscope will become negatively charged.

    Hmmm...
    Dont know how much i like that...


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