• Tough Physics Questions From Jamb 2004

    Physics

    Admin Admin
    29-01-2016 12:13:00 +0000

    Hello, today we will be looking at another physics questions from jamb 2004. These appears to be very tough questions. Our record shows that over 90% of test takers failed these questions.
    Try solving these questions and see if you can answer them.


    (Question 42) If 16mA of current flows through a conductor in one second, the number of electrons transported per second is.....?
    [1 electronic charge = 1.6 x 10-19C]
    A. 1.00 x 1020
    B. 2.56 x 10-18
    C. 2.56 x 10-17
    D. 1.00 x 1017

    (Question 43). The difference between x-rays and gamma rays is that
    A. X-rays arise from energy changes in the electronic structure of atoms while gamma rays come from the nucleus
    B. X-rays are electromagnetic radiations while gamma rays are negatively charges radiations.
    C. X-rays have lower frequencies than gamma rays
    D. X-rays are more penetrating than gamma rays

    UPDATED- ANSWERS OF QUESTIONS ABOVE

    (QUESTION 42)
    SOLUTION
    Option D is the correct answer
    EXPLANATION
    recall from formula that charge(q) = it
    where i = current
    t = time
    from question i = 16mA and t = 1s
    therefore q = 16 x 10-3A x 1s = 16 x 10-3C

    Now, 1 electron carries a charge of 1.6 x 10-19C

    i.e 1 electron = 1.6 x 10-19C
    ? = 16 x 10-3C
    Cross multiplying we have
    ? = 16 x 10-3/ 1.6 x 10-19
    ? = 10 x 10-3 + 19
    ? = 1017 electrons
    where ? is the number of electrons

    (Question 43)
    SOLUTION
    Option C is the correct answer.
    EXPLANATION
    From electromagnetic spectrum point of view, arranging in the other of decreasing frequency, Gamma rays top the field, followed by X- rays, Ultra violet, white light etc.
    Differences between X−rays and Gamma−rays as
    1. Gamma−rays cause more harm to human body than the X−rays.
    2. Gamma−rays have shorter wavelengths than the X−rays.
    3. X−rays are emitted by the electrons outside the nucleus, and gamma−rays are emitted by the excited nucleus itself.
    4. X−rays are used in hospitals for taking X−rays but gamma−rays are not.



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