Railway Board offers opulent and revered job posts to its aspirants. And it is not every year that we get the notification from Railway offering a good number of vacant seats to the multitude aspirants. But the current year 2018 brought a pleasant surprise with almost 90,000 seats to be filled by the valid candidates. Opportunity is here but you have to welcome it with a provident strategy.
Q1. A dentist’s mirror is a:
एक दंत चिकित्सक के दर्पण क्या है:
(a) cylindrical mirror/बेलनाकार दर्पण
(b) plane mirror/समतल दर्पण
(c) convex mirror/उत्तल दर्पण
(d) concave mirror/अवतल दर्पण
Sol. Dentist’s mirror is concave. It is also called converging mirror. This mirror is used in reflecting telescopes, gather light from a small source, to form optical cavities etc.
Q2.The lightest radioactive element is
सबसे हल्का रेडियोधर्मी तत्व कौन सा है?
(a) deuterium/ड्यूटेरियम
(b) polonium/पॉलोनियम
(c) tritium/ट्रिटियम
(d) uranium/यूरेनियम
Sol. Tritium is a radioactive form, or “isotope”, of hydrogen,it is the lightest radioactive element.
Q3.The temperature is measured with
तापमान किसके द्वारा मापा जाता है-
(a)Altimeter/अल्टीमीटर
(b) Pyrometer/पाइरोमीटर
(c) Ammeter/एम्मिटर
(d) Callipers/कैलिपरस
Sol. Pyrometer is an instrument for measuring high temperatures, especially in furnaces and kilns.
Q4. Kerosene oil floats on water because-
केरोसीन तेल पानी पर तैरता है क्योंकि –
(a) Its density is greater than the density of water/इसका घनत्व पानी के घनत्व से अधिक है
(b) Its density is less than the density of water/इसका घनत्व पानी के घनत्व से कम है
(c) Its density is equal to that of the density of water/इसका घनत्व पानी के घनत्व के बराबर है
(d) None of the above/उपरोक्त में से कोई भी नहीं
Sol. Kerosene oil floats on water because its density is less than the density of water.
Q5. At which temperature density of water is maximum?
किस तापमान पर पानी का घनत्व अधिकतम है?
(a) 4°C
(b) 0°C
(c) –4°C
(d) –8°C
Sol. The volume of water is minimum at 4°C. Hence the density of water is maximum at 4°C.
Q6. Why does an iron nail float on mercury while it sinks in water?
एक लोहे की कील पारे पर तैरती है जबकि वह पानी में डूब जाती है?
(a) Due to less chemical interaction of iron with mercury than it is with water / पानी की तुलना में पारा के साथ लोहे की कम रासायनिक परस्पर क्रिया के कारण
(b) Iron is heavier than water and lighter than mercury./लौह पानी से भारी है और पारे की तुलना में हल्का है.
(c) Iron has greater density than water and lesser than mercury. / लोहे का घनत्व पानी की तुलना में अधिक है और पारा से कम है.
(d) Mercury is heavier than water./ पारा पानी से भारी है.
Sol. An iron ball floats on mercury but gets immersed in water because the relative density of mercury is greater than the relative density of iron. However iron has a higher density than water.
Q7. ______ is the perpendicular distance between point of application of force and axis of rotation.
लगाये गये बल के बिंदु और घूर्णन अक्ष के बीच की लंबवत्त दूरी ___ है.
(a) Moment arm/आघूर्ण भुजा
(b) Moment of Inertia/जड़ता प्रवृत्ति
(c) Altitude/शीर्ष-लंब
(d) Base/आधार
Sol. Moment Arm is the perpendicular distance between point of application of force and axis of rotation.
Q8. An endoscope is a-
एंडोस्कोप एक है –
(a) Narrow telescope/ संकीर्ण दूरबीन
(b) Type of camera / कैमरा का प्रकार
(c) Simple microscope /सरल माइक्रोस्कोप
(d) None of these / इनमें से कोई नहीं
Sol. An endoscope is a medical device consisting of a long, thin, flexible (or rigid) tube which has a light source and a video camera. Images of the inside of the patient’s body can be seen on a screen. It is not suitable to categorize endoscope as a type of a camera.
Q9. A cut diamond shines brilliantly due to-
एक कट डायमंड शानदार ढंग से _______ की वजह से चमकता है –
(a) Total internal reflection /कुल आंतरिक प्रतिबिंब
(b) Absorption of light /प्रकाश का अवशोषण
(c) Some inherent property /कुछ अंतर्निहित गुण
(d) Its molecular structure / इसकी आणविक संरचना
Sol. The refractive index of diamond is very high. Diamond achieves brilliance partially from total internal refraction. It has been cut or designed in such a way that if light enters into it, incident light strikes many of the internal surfaces.
Q10. Which of the following is used to take 3-dimentional pictures-
निम्न में से क्या 3-आयामी तस्वीर लेने के लिए उपयोग किया जाता है-
(a) Photography / फोटोग्राफी
(b) Holography /होलोग्रफ़ी
(c) Radiography /रेडियोग्राफ़
(d) None of the above / उपरोक्त में से कोई नहीं
Sol. Holography is a technique of producing a three-dimensional image of an object. Holography can work with sound, light or any wavelength. It is also been used for three-dimensional natural films.
Q11. An astronaut sees the colour of the sky as-
एक अंतरिक्ष यात्री आकाश के रंग को ______ देखता है –
(a) Blue /नीला
(b) White/ सफेद
(c) Black /काला
(d) Red /लाल
Sol. The colour of the sky for an astronaut is black. It is because of the fact that in the space there is no atmosphere. Hence light doesn’t get scattered at all. In addition to this, in space, there are no air particles against which the sunlight can strike, get reflected or scattered. Hence, astronaut see everything black.
Q12. The red colour of the Sun at sunset and sunrise is due to-
सूर्यास्त तथा सूर्योदय के समय सूर्य के लाल रंग होने का कारण है-
(a) Scattering of light / प्रकाश का प्रकीर्णन
(b) Refraction of light /प्रकाश का अपवर्तन
(c) Total internal reflection of light / प्रकाश का कुल आंतरिक परावर्तन
(d) Dispersion of light / प्रकाश का परिक्षेपण
Sol. Red has the maximum wavelength. During sunrise and sunset, the rays have to travel a larger part of the atmosphere because they are very close to the horizon. Therefore light other than red is mostly scattered away. Most of the red light which is least scattered enters our eyes. Hence, the sun and the sky appear red.
पढने वाला चश्मा किस लेंस का बना होता है?
(a) Concave / अवतल
(b) Convex /उत्तल
(c) Plain / समतल
(d) None of these / इनमें से कोई नहीं
Sol. A convex lens is thicker in the middle and thinner at the edges. Rays of light that pass through the lens are brought closer together. A convex lens is also called a converging lens. A convex lens is also used in reading glasses & it also used to remove the defect of farsightedness.
Q14. The focusing in the eye is done by
नेत्र में ध्यान केंद्रित किसके द्वारा किया जाता है?
(a) Change in the convexity of the lens /लेंस की उत्तलता में बदलाव
(b) To and fro movement of the lens / लेंस के प्रति और पीछे की प्रवृत्ति द्वारा
(c) To and fro movement of the retina / रेटिना के प्रति और पीछे की प्रवृत्ति द्वारा
(d) Change in the refractive index of the eye fluid / आँख के तरल पदार्थ के अपवर्तक सूचकांक में बदलाव
Sol. The refractive or bending power of the cornea and humor is constant. However, that of the lens can be changed by changing its shape. That is making it more or less convex so that light can be properly focused on the retina. The greater the lens convexity or bulge the more bends the light. The flatter the lens, the less it bends that light.
Q15. The mirror, which is used in searchlights, is-
कौन सा दर्पण, सर्चलाइट्स में उपयोग किया जाता है
(a) Concave mirror/ अवतल दर्पण
(b) Convex mirror / उत्तल दर्पण
(c) Simple mirror / साधारण दर्पण
(d) None of these / इनमे से कोई नहीं
Sol. Concave mirror is used in the headlights of cars and in searchlights. A light placed at the focus of a concave lens can form a parallel beam and is used in car headlights and searchlights.
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