Laser physics
Tested in 3 real MPSC questions across 2 years (2014–2024). See it in context on the interactive Concept Graph →
Years it was asked
What you need to know first
Real questions that test this
औषधापासून ते संप्रेषणापर्यंत विविध क्षेत्रात लेझर हे एक मौल्यवान साधन बनले आहे. लेझर हा प्रकाश स्रोत आहे परंतु तो अनेक सामान्य प्रकाश स्रोतांपेक्षा खूप वेगळा आहे. आम्ही इतर प्रकाश स्रोत वापरतो म्हणून लेझरचा वापर प्रदीपनासाठी केला जात नाही. लेझर सामान्य प्रकारच्या प्रकाश स्रोतामधून उपलब्ध असलेल्या अखंड वारंवारता श्रेणीसह उच्च दिशात्मक आणि उच्च-तीव्रतेचा किरण (बीम) तयार करतात. लाइट किरण (बीम) ऐवजी लाइट पॉवर इलेक्ट्रोमॅग्नेटिक किरण (बीम) म्हणून ते अधिक प्रमाणात वापरले जातात. यांत्रिक उद्योगात लेसर किरणांच्या (बीमचा) एक विशेष ड्रिल बिट चा वापर हार्ड मटेरियल ड्रिल करण्यासाठी आणि लाकूड, काच, सिरॅमिक्स इत्यादी कापण्यासाठी केला जातो. लेसरचा वापर इलेक्ट्रोनिक्स उद्योग देखिल स्क्राइबिंग, सोल्डरिंग, ट्रिमिंग फोटolithोग्राफी, इ.साठी केला जातो. सैन्यात लेझरच्या वापरामध्ये प्रामुख्याने शस्त्रास्त्रांना श्रेणीबद्ध करणे, इच्छित लक्ष्यापर्यंत मार्गदर्शन करणे आणि लेझर किरण (बीम) स्वतःच एक शस्त्र म्हणून काम करणे इत्यादींचा समावेश होतो. अशा प्रकारे, लेसर हे एक उच्च-तंत्रज्ञान उपकरण आहे जे आपल्या जीवनावर अनेक प्रकारे परिणाम करते.
Read the following passage and answer the questions from 21 to 25 :
The word laser is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers are in fact generators of light. They are based on the amplification of light by means of stimulated radiation of atoms or molecules. In 1917 Einstein predicted the possibility of such stimulated radiation. In 1952, Ch. Townes, J.Gorden, and H.Zeiger in U.S.A and N.Basov and A.Prokhorov in USSR, independently suggested the principle of generating and amplifying microwave oscillations based on the concept of stimulated radiation. It lead to the invention of MASER (Microwave Amplification by Stimulated Emission of Radiation) in 1954. In 1958 Townes, Basov, and Prokhorov received Noble Prizes for their work in this field.
In 1960, Theodore Maiman of Hughes Research Laboratories produced the first laser using a ruby crystal as the amplifier and a flashlamp as the energy source. The first gas laser was developed in 1961 by A. Javan, W. Bennet, and H. Harriott of Bell Laboratories, using a mixture of helium and neon gases.
Laser has become a valuable tool in a variety of fields starting with medicine to communications. Laser is a light source but it is very much different from many traditional light sources. Laser is not used for illumination purposes as we use other light sources. Lasers produce a highly directional and high-intensity beam with a narrow frequency range than that available from the common source types of light sources. They are more widely used as a light power electromagnetic beam rather than a light beam. Laser beams are used in the mechanical industry such as a special type of drill bit to drill in hard materials, and cutting materials like wood, glass, ceramics, etc. The laser is also used in the electronics industry such as scribing, soldering, trimming photolithography, etc. Application of lasers in the military involves mainly ranging, guiding weapons to the intended target and laser beam itself acting as a weapon, and so on. Thus, the laser is a high-technology device affecting our lives in many ways.
लेझर व अणू किंवा रेणू यांचा काय संबंध आहे ? What is the relation between laser and atoms or molecules ?
a)लेझर अणू किंवा रेणू शिवाय उत्सर्जित होत नाहीत.
b)लेझर उत्तेजित किरणोत्सर्गांदारे प्रकाशाच्या प्रवर्धानावर आधारित आहेत.✓ Correct
c)लेझर सूक्ष्मतरंग विकीरीकरणावर आधारित आहेत.
d)वरीलपैकी नाही.
LASER stands for Light Amplification by Stimulated Emission of Radiation, indicating it works on the principle of stimulated emission.
त्रिस्तरीय लेझर मध्ये, अंशस्थिर अवस्था ______ मध्ये स्थिर असते. / In a three level laser, the metastable state is situated :
a)निम्नतम अवस्थेच्या खाली / below ground state
b)उत्तेजित स्थितीच्या वर / above excited state
c)उत्तेजित आणि निम्नतम स्थितीच्या मध्ये / in between excited and ground state✓ Correct
d)ऐन निम्नतम स्थितीत / exactly at ground state
In a three-level laser system, the metastable state is located between the upper excited state and the lower ground state.
प्रेरित उत्सर्जन प्रक्रियेसाठी त्रिस्तरीय लेझर मध्ये ______ . / For induced emission in a three level laser :
a)50% अणू अंशस्थिर स्थितीत असतात. / 50% of atoms should be in metastable state.
b)50% पेक्षा कमी अणू अंशस्थिर स्थितीत असतात. / < (less than) 50% of atoms should be in metastable state
c)50% पेक्षा जास्त अणू अंशस्थिर स्थितीत असतात. / > (more than) 50% of atoms should be in metastable state✓ Correct
d)अंशस्थिर स्थिती रिक्त असते. / metastable state must be vacant
In a three-level laser system, population inversion requires more than 50% of the atoms to be pumped into the metastable state so that stimulated emission can dominate over absorption.