TUGAS MATA KULIAHBAHASA INGGRIS

Disusun Oleh :

1. Retno Puji Lestari(14302241029)2. Endang Surani

(14302241030)3. Annisa Faurina Lestari(14302241031)Dosen Pengampu :Drs. Joko Sudomo, M.AJURUSAN PENDIDIKAN FISIKAFAKULTAS MATEMATIKA DAN ILMU PENGETAHUAN ALAMUNIVERSITAS NEGERI YOGYAKARTA2014/2015TittleX-Ray

IntroductionX-rays are electromagnetic waves having wavelengths 10-8 - 10-12 m and a frequency of about 1016 -1021 Hz. X-rays discovered by German physicist Wilhelm Roentgen C. on November 8, 1895. These rays can penetrate soft objects such as meat and skin but can not penetrate hard objects such as bones, teeth, and metal.

BodyX-rays were discovered through experiments using a tube. Roentgen observed a green flame on the tube that previously attracted the attention of Crookes. He tried to close the tube with black paper, with the hope that no visible light that can pass. But after closing it turns out there is something that can pass. He concluded that there are no visible rays are able to break through the black paper.

By the time he turned on the power source for the study of cathode ray tubes, he found that there was a type of fluorescent light on a screen made of barium Platino cyanida who happened to be nearby. If the power source is extinguished, the fluorescent light is gone. He soon realized that the kind of light that does not appear to have emerged from the cathode ray tube. Because never before known, then this light is named X-rays. But to appreciate his services in this invention, the X-rays that are often also called the Roentgen rays.

X-rays can be formed when charged particles. For example, electrons by atomic nuclei style influence material slowdown. X-rays are electromagnetic waves is none other than that formed through this process called X-ray bremsstrahlung. X-rays are formed in this way has the highest energy equal to the kinetic energy of charged particles at the time of deceleration.

X-rays are often used in various fields such as medicine, physics, chemistry, mineralogy, metallurgy, and biology. In the field of health, low energy X-rays are used to take still images known as radiographs. X-rays can penetrate the human body but is absorbed by the denser parts like bones. High energy X-rays are used to destroy cancer cells. This method is known as radiotherapy. In the field of industry, X-rays work knowing disability parts inside the machine and engine. Fixing cracks in metal pipes, concrete walls and high pressure. Checking cracks in the plastic structure and sap. In other fields, X-rays are also used in the field plane, soft X-rays are used to inspect the goods and passenger bag.

ConclusionAlthough beneficial , the use of X-rays should pay attention to the procedure . Because permeable large enough X-rays use excessive to humans can lead to , destruction of cells in the body , changes in the genetic structure of a cell , blood cancer , bad impressions such as hair loss , skin becomes red and ulcerous . X-ray radiation can kill monocytes (a type of white blood cells ) are found on the walls of arteries . This was found to lead to increased levels of monocyte chemo-attractant-protein 1(MCP-1) which can lead to cardiovascular disease . Therefore , the transmission of X-rays in the treatment of humans cultivated as short as possible .

Translate.JudulSinar-X

PengantarSinarX adalah gelombang elektromagnetik yang mempunyai panjang gelombang 10-8-10-12 m dan frekuensi sekitar 1016 -1021 Hz. Sinar-X ditemukan oleh fisikawan berkebangsaan Jerman Wilhelm C. Roentgen pada tanggal 8 November 1895. Sinar ini dapat menembus benda-benda lunak seperti daging dan kulit tetapi tidak dapat menembus benda-benda keras seperti tulang, gigi, dan logam.

IsiSinar-X ditemukan melalui percobaan menggunakan tabung. Roentgen mengamati nyala hijau pada tabung yang sebelumnya menarik perhatian Crookes. Dia mencoba menutup tabung itu dengan kertas hitam, dengan harapan agar tidak ada cahaya tampak yang dapat lewat. Namun setelah ditutup ternyata masih ada sesuatu yang dapat lewat. Dia Menyimpulkan bahwa ada sinar-sinar tidak tampak yang mampu menerobos kertas hitam tersebut.

Pada saat Dia menyalakan sumber listrik tabung untuk penelitian sinar katoda, Dia mendapatkan bahwa ada sejenis cahaya berpendar pada layar yang terbuat dari barium platino cyanida yang kebetulan berada di dekatnya. Jika sumber listrik dipadamkan, maka cahaya pendar pun hilang. Dia segera menyadari bahwa sejenis sinar yang tidak kelihatan telah muncul dari dalam tabung sinar katoda. Karena sebelumnya tidak pernah dikenal, maka sinar ini diberi nama sinar-X. Namun untuk menghargai jasanya dalam penemuan ini maka seringkali sinar-X itu dinamai juga Sinar Roentgen.

Sinar-X dapat terbentuk apabila partikel bermuatan. Misalnya elektron oleh pengaruh gaya inti atom bahan mengalami perlambatan. Sinar-X yang tidak lain adalah gelombang elektromagnetik yang terbentuk melalui proses ini disebut sinar-X bremsstrahlung. Sinar-X yang terbentuk dengan cara demikian mempunyai energi paling tinggi sama dengan energi kinetik partikel bermuatan pada waktu terjadinya perlambatan.

KesimpulanMeskipun besar manfaatnya, penggunaan sinar-X harus memperhatikan prosedur . Karena daya tembusnya cukup besar penggunaan sinar-X yang berlebihan terhadap manusia dapat menyebabkan, pemusnahan sel-sel dalam badan, perubahan struktur genetik suatu sel, penyakit kanker darah, kesan-kesan buruk seperti rambut gugur, kulit menjadi merah dan berbisul. Radiasi sinar-X dapat membunuh monosit (salah satu jenis sel darah putih) yang terdapat pada dinding arteri. Hal ini ternyata dapat mengakibatkan meningkatnya kadar monocyte chemo-attractant protein 1 (MCP-1) yang dapat mengarah kepada penyakit kardiovaskular. Oleh karena itu, pemancaran sinar-X pada pengobatan manusia diusahakan sesingkat mungkin.