Question
(c) Rajah 13.5 menunjukkan sebiji bola tenis berjisim 5.5 \times 10^{-2} kg bergerak dengan halaju 40ms^{-1} apabila dipukul oleh sebatang raket.
Diagram 13.5 shows a tennis ball of mass 5.5 \times 10^{-2} kg moves
with a velocity of 40ms^{-1} when hit by a racket.
[h=6.63 \times 10^{-34} Js dan / and c= 3 \times 10^{8}ms^{-1}]
Hitung
Calculate
(i) panjang gelombang de Broglie bola tenis itu.
the de Broglie wavelength of the tennis ball.
Answer
Hi Farhaini,
Your working is correct for this question as well haha, because I’m guessing what the mark scheme did was they used the speed of light instead of the 40ms^{-1} velocity, which is bogus since the ball doesn’t travel at speed of light 
and the question is asking de Broglie wavelength of the ball, not photon 
so the mark scheme’s answer is not logic in my opinion.
Hope this clears things up! 
Yeaah its soo clear THANK YOU VERY MUCHH 
