20011 phy MC

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1. Please solve the above mc with explanation

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2. As it has been mentioned that one of the light experiences pie phase change, then maximum reading (constructive interference) at a point on AB is shown if the path difference equals m(wavelength) instead of (m+1/2)(wavelength?)

更新:

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I still don't understand the solution to question 44. Could you explain more in detail please?

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  • 天同
    Lv 7
    9 年前
    最愛解答

    36. When the iron core is removed, value of inductance L decreases. Hence, resonance frequency increases.

    Option A.

    7. Option C

    http://hk.knowledge.yahoo.com/question/question?qi...

    30. Path traversed = R.[2(theta)], where R is the radius of the circular arc

    Since mv^2/R = qvB

    m is the mass od the particle, q is its charge, v is ts speed, and B is the magnetic flux density.

    i.e. v = qB.R/m

    Time spent in magnetic field = R[2.(theta)]/v = 2R.(theta).m/qBR

    Answer is option D

    13. Wavelength = 4x10^-7 m

    hence, frequency = 3x10^8/(4x10^-7) Hz = 7.5x10^14 Hz

    Answer is option B

    3. Change in potential energy = 10g(1.2/2-0.5/2) J = 70 J

    Option C

    33. Each of the two secondary coils supplies power to the output alternatively.

    Hence, voltage output = 220 x (100/1100) v = 20 v

    Option A

    Microwave experiment:

    Constructive interference: path difference = (m+1/2).入, m = 0, 1,1,3...

    Destructive interference : path difference = m入

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