Physics [Light] Questions for Railway ALP Stage-II Exam : 7th December 2018

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Q1. What is the wavelength of visible spectrum?
दृश्य स्पेक्ट्रम की तरंगदैर्ध्य क्या है
(a) 1300 Å to 3000 Å
(b) 3900 Å to 7600 Å
(c) 7800 Å to 8000 Å
(d) 8500 Å to 9800 Å
Show Answer
Ans.(b)
Sol. The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 3900 Å to7600 Å .

Q2. An electron microscope gives higher magnification than an optical microscope, because
एक इलेक्ट्रॉन माइक्रोस्कोप एक ऑप्टिकल माइक्रोस्कोप की तुलना में उच्च आवर्धन देता है, क्योंकि
(a) it uses more powerful lenses/ यह अधिक शक्तिशाली लेंस का उपयोग करता है
(b) the velocity of electron is smaller than that of visible light/ इलेक्ट्रॉन की वेग दृश्य प्रकाश की तुलना में छोटी है
(c) the electrons have more energy / इलेक्ट्रॉनों में अधिक ऊर्जा होती है
(d) the wavelength of electrons is smaller as compared to the wavelength of visible light / दृश्य प्रकाश की तरंगदैर्ध्य की तुलना में इलेक्ट्रॉनों की तरंग दैर्ध्य छोटी है

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Ans.(d)
Sol. An electron microscope gives higher magnification than an optical microscope, because the wavelength of electrons is smaller as compared to the wavelength of visible light .

Q3. The mass-energy relation is the outcome of 
मास-ऊर्जा संबंध किस का नतीजा है
(a) quantum theory / क्वांटम सिद्धांत
(b) general theory of relativity/ सापेक्षता का सामान्य सिद्धांत
(c) field theory of energy / ऊर्जा के क्षेत्र सिद्धांत
(d) special theory of relativity / सापेक्षता का विशेष सिद्धांत

Show Answer
Ans.(d)
Sol. Energy and Mass Are Relative. The equation E = mc2 (special theory of relativity )states that the amount of energy possessed by an object is equal to its mass multiplied by the square of the speed of light.

Q4. A simple microscope consists of
एक साधारण माइक्रोस्कोप किस से बना होता हैं?
(a) a short focus convex lens / एक लघु फोकस वाला उत्तल लेंस
(b) a long focus convex lens/ एक लंबे फोकस वाला उत्तल लेंस
(c) a short focus concave lens / एक लघु फोकस वाला अवतल लेंस
(d) a long focus concave lens/ एक लंबे फोकस वाला अवतल लेंस

Show Answer
Ans.(a)
Sol. Simple microscope is used for observing magnified images of the objects. It consists of a short focus convex lens.
The magnifying power of simple microscope can be determined in two cases. When the final image is formed at least distance of district vision (D),
Then M=1+D/f
When the final image is formed at infinity, the M=D/f
Where M = magnifying power
D = distance of distinct vision
f = focal length of the lens



Q5. The speed of light with the rise in the temperature of the medium 
किसी माध्यम के तापमान में वृद्धि के साथ प्रकाश की गति
(a) increases/बढती है
(b) decreases /घटती है
(c) remains constant/सामान रहती है
(d) drops suddenly / अचानक गिरता है

Show Answer
Ans.(c)
Sol. Speed of light does not depends on the temperature. It is a constant which is denoted by ‘c’.



Q6. Which one of the following is used for sun glasses? 
धूप के चश्मे के लिए इनमें से कौन सा उपयोग किया जाता है?
(a) pyrex glass/ पाइरेक्स ग्लास
(b) flint glass/ फ्लिंट ग्लास
(c) Crooks glass / क्रूक ग्लास
(d) Crystal glass/ क्रिस्टल ग्लास

Show Answer
Ans.(c)
Sol. Crookes glass mainly cerium oxide (CiO2) is present which sharply absorbs the ultraviolet rays from the sunlight so utilised in making lenses of eye glasses.

Q7. What is viewed through an electron microscope?
एक इलेक्ट्रॉन माइक्रोस्कोप के माध्यम से क्या देखा जा सकता है?
(a) Inside of the human eye/ मानव आंख के अंदर
(b) Structure of bacteria and viruses / बैक्टीरिया और वायरस का ढांचा
(c) Inside of human stomach / मानव पेट के अंदर
(d) None of these/इनमें से कोई नहीं
Show Answer
Ans.(b)
Sol. The electron microscope is a type of microscope that uses a beam of electrons to create an image of the specimen. It is capable of much higher magnifications and has a greater resolving power than a light microscope, allowing it to see much smaller objects in finer detail.


Q8. Which combination of colour is the most convenient during day and night time?
रंग का कौन सा संयोजन दिन और रात के समय के दौरान सबसे सुविधाजनक है?
(a) Organe and blue/ नारंगी और नीला
(b) White and black/सफ़ेद और काला
(c) Yellow and blue/पीला और नीला
(d) Red and green/लाल और हरा
Show Answer
Ans.(d)
Sol. Red and green colour is the most convenient during day and night time .

Q9. The blue colour of water in the sea is due to 
समुद्र में पानी का नीला रंग किस के कारण होता है
(a) absorption of other colours except blue by water molecules/ पानी के अणुओं द्वारा नीले रंग को छोड़कर अन्य रंगों का अवशोषण
(b) scattering of blue light by water molecules / पानी के अणुओं द्वारा नीली रोशनी की बिखरने
(c) reflection of blue light by impurities in sea water/ समुद्र के पानी में अशुद्धियों द्वारा नीली रोशनी का प्रतिबिंब
(d) reflection of blue sky by sea water/ समुद्र के पानी से नीले आसमान का प्रतिबिंब
Show Answer
Ans.(a)
Sol. The ocean looks blue because red, orange and yellow (long wavelength light) are absorbed more strongly by water than is blue (short wavelength light). So when white light from the sun enters the ocean, it is mostly the blue that gets returned.

Q10. Rainbow is seen after rain because of hanging molecules of water which act as
इंद्रधनुष बारिश के बाद देखा जाता है, यह पानी के गिरते अणुओं के कारण होता है जो _____ के रूप में कार्य करते हैं
(a) lenses/लेंस
(b) prism/ प्रिज्म
(c) mirrors/ दर्पण
(d) slabs / स्लैब
Show Answer
Ans.(b)
Sol. Rainbow is seen after rain because of hanging molecules of water which act as prism.

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