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2. Jasad hitam ialah sejenis jasad unggul yang penyerap dan pemancar semua jenis sinaran elektromagnet.
Jika suhu jasad hitam semakin meningkat, ia akan bertukar warna dari merah ke berwarna kuning, putih
dan akhirnya putih kebiru-biruan.
A black-body is an absorber and transmitter of all types of electromagnetic radiation. If the temperature of the
black-body increases, it will change color from red to yellow, white and eventually bluish white.
Graf di bawah menunjukkan keamatan sinaran melawan panjang gelombang bagi jasad hitam unggul.
Semakin tinggi suhu jasad hitam, keamatan sinaran semakin tinggi dan kedudukan puncak graf beralih
ke arah gelombang yang lebih pendek.
The graph below shows the radiation intensity against the wavelength of the black-body. Higher the temperature
of the black body, higher the intensity of radiation and the position of peak of the graph shifts towards shorter
wavelength.
Bentuk graf tidak dapat dijelaskan menggunakan teori
Keamatan
©PAN ASIA PUBLICATIONS
Intensity klasik kerana kelakuan cahaya sebagai gelombang
6000 K dengan tenaga selanjar. Teori klasik meramalkan
bahawa apabila panjang gelombang semakin pendek,
Ramalan Teori Klasik keamatan sinaran suatu jasad (hitam) meningkat
Classical Theory prediction
6000 K tanpa had pada sebarang suhu. Kegagalan teori
klasik menyebabkan Max Planck memperkenal Teori
5000 K Kuantum Planck.
The shape of the graph cannot be explained by using
classical theory because of the behavior of light as a wave
4000 K with continuous energy. Classical theory predicts that as
3000 K
0 wavelengths get shorter, the radiation intensity of a black-
500 1000 1500 2000 2500 3000 body increases indefinitely at any temperature. The failure
Panjang gelombang/ nm of classical theory caused Max Planck introduce Planck's
Wavelength/ nm quantum theory.
3. Max Planck menyatakan bahawa tenaga sinaran gelombang elektromagnet adalah tidak selanjar tetapi
dalam bentuk kuantum. Beliau telah terbitkan persamaan untuk tenaga yang dibebaskan oleh jasad
hitam dalam bentuk kuantum tenaga yang bergantung kepada frekuensi gelombang,
Max Planck stated that energy of electromagnetic radiation is not continuous but in terms of quantum. He has
derived an equation for the energy released by a black body in quantum form which is depends on the frequency of
the wave,
E = tenaga foton/ photon energy
E = hf f = frekuensi gelombang elektromagnet/ frequency of electromagnetic waves
h = pemalar Planck/ Planck’s constant = 6.63 × 10 −34 J s
4. Kuantum tenaga adalah tenaga tidak dipindahkan secara berterusan tetapi dalam bentuk paket diskrit
yang bergantung kepada frekuensi gelombang.
Quantum of energies are not transmitted continuously but in the form of a discrete packet depending on the wave
frequency of waves.
5. Sifat gelombang elektromagnet bergantung kepada panjang gelombang dan halaju rambatan dalam
ruang bebas adalah bersamaan dengan halaju cahaya. Halaju rambatan gelombang
The nature of the electromagnetic wave depends on the wavelength and propagation velocity in the free space at
the same velocity as the light velocity. Wave propagation speed
λ = panjang gelombang elektomagnet/ wavelength of electromagnetic wave
c = fλ f = frekuensi gelombang elektromagnet/ frequency of electromagnetic waves
8
c = halaju cahaya/ speed of light = 3.0 × 10 m s –1
6. Perbezaan antara teori klasik dan teori kuantum Planck
The differences between classical theory and Planck’s quantum theory
Teori klasik/ Classical theory Teori kuantum planck/ Planck’s quantum theory
Selanjar/ Continuously Diskrit atau kuantum/ Discrete or quanta
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