# General Science Questions for Railway Exam 2018 : 6th April

## General Science Questions for Railway 2018:

Dear Students,

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. The exam will be conducted in the months of April and May 2018.

रेलवे बोर्ड अपने उम्मीदवारों के लिए भव्य और प्रतिष्ठित कार्य पदों की पेशकश करता है. और हर साल ऐसा नहीं होता है कि हमें रेलवे की ओर से अधिसूचना मिलती है. लेकिन वर्तमान वर्ष 2018 आपके लिए बहुत सुखद वर्ष है क्योंकि इसमें लगभग 90,000 सीटों को वैध उम्मीदवारों द्वारा भरा जाएगा. आपके पास बहुत अच्छा अवसर है और आपको इसे एक बेहतर रणनीति से प्राप्त करना होगा. परीक्षा अप्रैल और मई 2018 के महीने में आयोजित की जायेगी.

Q1. The working principle of a washing machine is-
एक कपड़े धोने की मशीन के कार्य का सिद्धांत क्या है-
(a) Centrifugation / केन्द्रापसारण
(b) Dialysis / अपोहन
(c) Reverse Osmosis / विपरीत परासरण
(d) Diffusion / विसरण

Show Answer
Ans.(a)
Sol. The working principle of a washing machine is based on centrifugation force. The term centrifugal force is used to refer to an inertial force or fictitious force, particular to a particle moving on a circular path that has the same magnitude and dimensions as the force that keeps the particle on its circular path but the point in the opposite direction.

Q2. Which physical quantity is represented by the ratio of momentum and velocity of the body?
वस्तु की गति और संवेग के अनुपात से किस भौतिक मात्रा का प्रतिनिधित्व किया जाता है?
(a) Velocity / वेग
(b) Acceleration / त्वरण
(c) Mass  /द्रव्यमान
(d) Force / बल

Show Answer
Ans.(c)
Sol. Momentum is a vector quantity that is the product of Mass and the Velocity of an object or particle.
Momentum = Mass × Velocity
So, Mass = (Momentum )/Velocity

Q3. The energy of wind is-
हवा की ऊर्जा क्या है-
(a) Only potential / केवल स्थितिज
(b) Only kinetic / केवल गतिज
(c) Electrical / विद्युतीय
(d) Potential and kinetic both / स्थितिज और गतिज दोनों

Show Answer
Ans.(b)
Sol. The kinetic energy is the energy in moving objects or mass. The kinetic energy of the wind (wind energy) can be converted into electrical or mechanical energy.

Q4. Photovoltaic cells are:
फोटोवोल्टेइक सेल क्या हैं:
(a) Solar cells / सौर सेल
(b) Thermal cells / उष्मा सेल
(c) Sulphur cells / सल्फर सेल
(d) Molar cells /मोलर सेल

Show Answer
Ans.(a)
Sol. The conversion of light energy into electrical energy is based on the phenomenon  called photovoltaic effect. Silicon is most widely used semiconductor material for construction photovoltaic cell.

Q5. What is the correct equation for finding the acceleration?
त्वरण ज्ञात करने के लिए सही समीकरण क्या है?
(a) a = (v-u)/t
(b) a = u + vt
(c) a = (v+u)/t
(d) a=(v+u)/2

Show Answer
Ans.(a)
Sol. As we know v = u + at or at = v – u
∴a=(v-u)/t
Where, v = ultimate velocity of the particle
u = initial velocity of the particle
a = Acceleration, t = time

Q6. A drop of water is spherical in shape. This is due to:
पानी की बूंद किसके कारण गोलाकार आकृति की होती है:
(a) Surface tension / सतह तनाव
(b) Low temperature / कम तापमान
(c) Air resistance / हवा प्रतिरोध
(d) Viscosity of water / पानी की श्यानता

Show Answer
Ans.(a)
Sol. The shape of a drop of rain is constrained by the surface tension, which tries to give it the shape for which the surface area is minimum for the given volume. The spherical shape has the minimum surface area. That’s why rain drops acquire spherical shape.

Q7. Velocity of light is maximum in-
प्रकाश की गति किसमें अधिकतम होती है-
(a) Diamond/हीरा
(b) Water/पानी
(c) Vacuum/शून्यक
(d) Hydrogen/हाइड्रोजन

Show Answer
Ans.(c)
Sol. The speed of light in vacuum is maximum (c = 3 × 108 ms–1). The speed of light decreases gradually in optically denser mediums like water or glass. It is least in diamond.

Q8. 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) 655 nm/655 एनएम
(b) 555 nm/555 एनएम
(c) 455 nm /455 एनएम
(d) 755 nm/755 एनएम

Show Answer
Ans.(b)
Sol. Eye is most sensitive to yellow-green light that is light of wavelength 555nm.

Q9. The wave length extension of visible light is-
दृश्यमान प्रकाश का तरंगदैर्ध्य विस्तार कितना है-
(a) Between 200–900 nm / 200-900 एनएम के बीच
(b) Between 250–850 nm / 250-850 एनएम के बीच
(c) Between 300–800 nm / 300-800 एनएम के बीच
(d) Between 390–780 nm / 390-780 एनएम के बीच

Show Answer
Ans.(d)
Sol. Visible light is that part of electromagnetic radiation which can be seen by human eyes. A normal human eye can see the electromagnetic radiation between 390–780 nm of wavelength.

Q10. The speed of light will be minimum while passing through-
किससे गुजरते समय प्रकाश की गति न्यूनतम होती है-
(a) Glass / कांच
(b) Vacuum / शून्यक
(c) Water / पानी
(d) Air / हवा

Show Answer
Ans.(a)
Sol. Any of the object or material which has the highest refractive index has the minimum speed of light. The glass has the highest refractive index among other like, vacuum, water and air.

Q11. The radius of curvature of the plane mirror is:
समतल दर्पण की वक्रता त्रिज्या कितनी होती है:
(a) Zero/शून्य
(b) One/ एक
(c) Infinity/ अनन्तता
(d) Between one and infinity/ एक और अनंत के बीच

Show Answer
Ans.(c)
Sol. As we know that the reflection in the plane mirror forms at the same distance at which the object is placed in front of the mirror. That is,
d_o = distance of the object from the mirror
d_i = distance of reflection from the mirror and focus distance for a curved mirror or the relationship between r, d_o and d_i is 1/d_o +1/d_i =2/r  (here r=radius of curvature)
But for the plane mirror
d_o=-d_i
Thus 2/r=0
Or, r=2/0(Undefined)
Or r = ∞

Thus, the radius of curvature of plane is considered as infinity.

Q12. निम्नलिखित में से क्या विद्युत का सर्वश्रेष्ठ सुचालक है?
(a) Mica/मैका
(b) Copper / कॉपर
(c) Gold / सोना
(d) Silver /चांदी

Show Answer
Ans.(d)
Sol. Electrical conductivity is a measure of the amount of electrical current under a material can carry. The most electrically conductive element is silver.

Q13. Which is not used as Atomic fuel?
इनमें से क्या परमाणु ईंधन के रूप में प्रयोग नहीं किया जाता है?
(a) Uranium / यूरेनियम
(b) Thorium/ थोरियम
(c) Plutonium / प्लूटोनियम
(d) Lead /लेड

Show Answer
Ans.(d)
Sol. The most common nuclear fuels are uranium – 235 (235U) and plutonium -239(239Pu). Thorium is more abundant in nature than uranium. Thorium can be used as a nuclear fuel through breeding to uranium-233 (U-233). Lead is not used as a nuclear fuel.

Q14. The gas used in discharge tubes for optical decoration and advertising is-
ऑप्टिकल सजावट और विज्ञापन के लिए निर्वहन ट्यूबों में कौन सी गैस उपयोग होती है-
(a) Carbon dioxide/ कार्बन डाइआक्साइड
(b) Ammonia / अमोनिया
(c) Sulphur dioxide / सल्फर डाइऑक्साइड
(d) Neon / नियोन

Show Answer
Ans.(d)
Sol. The neon gas is used in discharge lamps, tubes and in fluorescent bulbs.

Q15. A radio station broadcast at 30 metre band. The frequency of the carrier wave transmitted by this station is:-
एक रेडियो स्टेशन 30 मीटर बैंड पर प्रसारण करता है. इस स्टेशन द्वारा प्रेषित वाहक तरंग की आवृत्ति कितनी होगी है:-
(a) 10 KHz
(b) 100 KHz
(c) 10 MHz
(d) 100 MHz

Show Answer
Ans.(c)
Sol. According to formula = > n = c/I
[where n=frequency,c=speed of light;I=wavelength]
=(3×10^8)/30=10× 10^6=10 MHz

You may also like to read: