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  1. ... the answer is D All of them could actually be show in ray diagram. 5. when a glass block put between the lens and S, we could consider...

  2. conservation of momentum initial momentum = mu final momentum = mv1+2mv2 u = v1 +2v2 using above forumla, eliminating ans A conservation of kinetic energy: final energy must be less than initial energy initial energy = 1/2 m u^2 final energy = 1/2 m v1^2 + m v2^2 u^2 = v1^2 + 2v2^2 ans B & D...

  3. ...positive.) So comparing the solid waveform (representing the moment shown in the question) and the dotted waveform (representing the moment a little...

  4. ... emf is related to the rate of change of magnetic flux linkage as shown in the equation below: 圖片參考:http://i117.photobucket.com/albums/o61/billy_hywung...

  5. 如圖中所示,若電池有內阻,可以考慮加一個電阻 r,在電池旁以方便計算。 圖片參考:http://hk.geocities.com/namsm4e/p0125.jpg 所以電路的 總電阻為 10 + r,電壓為 3v,電流為 0.214A,依歐姆定律 V = I R 3 = 0.214(10 + r) r = 4.0Ω 其實這...

  6. Let original P.E. = mgH. As the ball rebounds 1/4 of its original height (i.e. 1/4 × H), P.E. at 1/4 of original height = mg(1/4 × H) = 1/4 × mgH = 1/4 of original P.E. By conservation of energy, K...

  7. It should be B, (1) and (2) (1), Work done = Fs = area under the graph = xy /2 J So, (1) is correct. (2). By Newton's 2nd law of motion F = ma From the graph, F is +ve throughout the journey, so acceleration...

  8. Ans: B (1) is wrong. d.c. current cannot be adopted in transformer as d.c. current in the primary current produce constant magnetic field (i.e. no magnetic flux change) inducing zero e.m.f. in the secondary coil. energy cannot be transfer, let alone its step down process. (2...

  9. (a)Vab=1*3=3V (b)I1=1+3/6=1.5A (c)I2=I1=1.5A (d)Vc=1.5*4=6V (e)P=6*1.5=9W

  10. Buy a multi-socket adapter and open it. All metals are conductors. Where can find more information about "Circuits" go to http://www.vias.org/electronics.html