# Physics Questions for Railway & SSC CGL Exam 2018: 24th October 2018 | in Hindi

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Q1. When light passes from one medium to another medium, which one of the followings does not change:
जब प्रकाश एक माध्यम से दूसरे माध्यम में गुजरता है, तो निम्नलिखित में से क्या परिवर्तित नहीं होता है:
(a) Intensity/ गहनता
(b) Velocity/ गति
(c) Wavelength/ तरंग दैर्ध्य
(d) Frequency/ आवृत्ति
Ans.(d)
Sol. When light passes from air to glass or one medium to another, then the frequency of the light remains constant but wavelength and velocity are changed.

Q2. The visible range of solar radiation is-
सौर विकिरण की दृश्य सीमा है
(a) 100-400 nm
(b) 400-700 nm
(c) 740-10000 nm
(d) None of the above/ उपरोक्त में से कोई नहीं

Ans.(b)
Sol. The electromagnetic spectrum encompasses all type of radiations. The part of the spectrum that reaches earth from the sun is between 100 nm to 〖10〗^6 nm. This band is broken into three ranges – Infrared (above 700 nm), Visible (400 to 700 nm), Ultraviolet (below 400 nm).

Q3. Total internal reflection can take place when light travels from:
कुल आंतरिक प्रतिबिंब तब हो सकता है जब प्रकाश ________ से यात्रा कर रहा है:
(a) Diamond to glass/ डायमंड से ग्लास
(b) Water to glass/ पानी से ग्लास
(c) Air to water/ हवा से पानी
(d) Air to glass/ हवा से ग्लास

Ans.(a)
Sol.  Total internal reflection takes place when a ray of light is travelling from denser to thinner medium and angle of incidence is greater than the critical angle, the ray is completely reflected from surface and meet each other as if the surface is a mirror. So according to options, the situation of option (a) is correct where total internal reflection takes place, it is because diamond is denser than glass.

Q4. Human eye is most sensitive to visible light of the wavelength
मानव आंख किस तरंग दैर्ध्य के दृश्यमान प्रकाश के प्रति अधिक संवेदनशील है?
(a) 605nm/ एनएम
(b) 555nm/ एनएम
(c) 450nm / एनएम
(d) 750nm / एनएम

Ans.(b)
Sol. Under daylight conditions, the average normal sighted human eye is most sensitive at a wavelength of 555 nm.

Q5. PARSEC is the unit of:
PARSEC किसकी इकाई है
(a) Distance / दूरी
(b) Time /समय
(c) Light intensity / प्रकाश की तीव्रता
(d) Magnetic force / चुंबकीय बल

Ans.(a)
Sol. A PARSEC is a unit of length used to measure the astronomically large distance of objects outside the solar system.
One parsec is equal to about 3.26 light-years (30 trillion km or 19 trillion miles) in length.

Q6. Which  unit of measurement is multiplied by 0.39 to convert it to ‘inches’?
किस मापन इकाई को ‘इंच’ में परिवर्तित करने के लिए 0.3 इंच से गुणा किया जाता है?
(a) Millimetre / मिलीमीटर
(b) Centimetre / सेंटीमीटर
(c) Metre / मीटर
(d) Decimetre /डेसीमीटर

Ans.(b)
Sol. 1 Centimetre = 0.39 inch, so we can multiply centimeter by 0.39 to convert it to inches’.

Q7. How can the height of a person who is six feet tall, be expressed (approximately) in nanometer?
छह फीट लंबे व्यक्ति की ऊंचाई, नैनोमीटर में (लगभग) किस रूप में व्यक्त की जा सकती है?
(a) 183×10⁶nm
(b) 234×10⁶nm
(c) 183×10⁷nm
(d) 181×10⁷nm
Ans.(c)
Sol. 1 nonaometre = 10-9 metre
1 Feet = 0.305 metre
1 Feet = 30.5 × 107 nanometre
6 Feet = 6 × 30.5 × 107 nanometre
= 183 × 107 nanometre
Q8. A nanometer is equal to-
एक नैनोमीटर किसके बराबर है- –
(a) 10^(-6) cm
(b) 10^(-7) cm
(c) 10^(-8) cm
(d) 10^(-9) cm
Ans.(b)
Sol. A nanometer is equal to- 10-7) cm
Q9. Ampere is the unit of-
एम्पियर किसकी इकाई है
(a) Voltage / विद्युत दाब
(b) Electric current / विद्युत प्रवाह
(c) Resistance / प्रतिरोध
(d) Power / शक्ति
Ans.(b)
Sol. Ampere is a unit to measure electric current. If one Ampere current is flowing in any conducting wire, it means 6.25 × 10-18 electrons are entering per second from one direction and same amount of electrons flows from the other end per second.

Q10. The nature of radiation of light is-
प्रकाश का विकिरण किस प्रकृति का है-
(a) Like wave/तरंगीय
(b) Like particle/कणीय
(c) Like both of wave and particle/तरंगीय और कणीय दोनों
(d) Like neither of wave nor of particle/ना तरंगीय और ना ही कणीय
Ans.(c)
Sol. The light has a dual nature, sometimes it behaves only as wave and sometimes as light. In the later part of the 19th century and in the beginning of 20th century, it was realized that black body radiation and the photelectric effect can be understood only on the basis of particle model of light. Some experiments require light to be a wave, while others require light to be a particle. This led to the acceptance of dual nature of light.

Q11. Light appears to travel in a straight line because-
प्रकाश एक सीधी रेखा में यात्रा करता प्रतीत होता है क्योंकि
(a) It consists of small particles. / इसमें छोटे कण होते हैं
(b) The velocity of light is very large. / प्रकाश का वेग बहुत अधिक है
(c) The wavelength of light is very small. / प्रकाश का तरंगदैर्ध्य बहुत कम है
(d) Light is reflected by the surroundings. / प्रकाश आसपास की वस्तुओं द्वारा प्रतिबिंबित होता है
Ans.(c)
Sol. Due to its very small wavelength, the light appears to travel in a straight line.
Q12. Decibel is a –
डेसीबेल क्या है?
(a)musical note / संगीत नोट
(b)musical instrument / संगीत वाद्ययंत्र
(c)unit of intensity of sound / ध्वनि की तीव्रता की इकाई
(d)unit of elasticity / लोच की इकाई
Ans.(c)
Sol. The decibel ( dB) is used to measure sound level.

Q13. FM broadcasting service uses the range of frequency bands between –
एफएम प्रसारण सेवा किस बैंड आवृत्ति की सीमा का उपयोग करता है?
(a) 109-139 MHz / 109-139 मेगाहर्ट्ज
(b) 54-75 MHz / 54-75 मेगाहट्र्ज
(c) 76-87 MHz / 76-87 मेगाहर्ट्ज
(d) 88-108 MHz / 88-108 मेगाहट्र्ज
Ans.(d)
Sol. FM broadcasting service uses the range of frequency bands between 88 to 108 MHz. There is a number of band allocation used around the globe:
1. 87.5 – 108 MHz: – It is the “standard” VHF FM band. The one Which is most widely used around the globe.
2. 76-90 MHz- This VHF FM band is used in Japan.
3. 65.8 – 74.0 MHz- This VHF FM band is known as the OIRT band. It was used in Eastern Europe although few other countries such as Russia, Ukraine also use it.
Q14. Following rays are used in the diagnosis of intestinal diseases.
आंतों के रोगों के निदान में निम्नलिखित में से किन किरणों का उपयोग किया जाता है?
(a) X-rays / एक्स-रे
(b) α-rays / α-किरणें
(c) β-rays / β- किरणें
(d) γ-rays / γ-किरणें
Ans.(a)
Sol. X-rays are a form of electromagnetic radiations, which are used in the diagnosis of intestinal diseases.

Q15. CT scan is done by using–
निम्न लिखित में से किसका उपयोग करके सीटी स्कैन किया जाता है?
(a) Infra-red Rays / इन्फ्रा-लाल किरणें
(b) Ultrasonic waves / अल्ट्रासोनिक तरंगें
(c) Visible Light / दृश्यमान प्रकाश
(d) X-Rays / एक्स-रे
Ans.(d)
Sol. CT Scan or computed tomography are special x-rays tests that produce cross-sectional images of the body using x-rays and a computer.