Physics Questions [Gravitation] for Railway ALP Stage-II Exam : 17th November 2018

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 1,27,278 seats to be filled by the valid candidates. Opportunity is here but you have to welcome it with a provident strategy.

Q1. A thief stole a box with valuable article of weight ‘W’ and jumped down a wall of height h. Before he reach the ground he experienced a load of
एक चोर ने वजन ‘W’ के मूल्यवान वस्तु के साथ एक बॉक्स चुरा लेता हैऔर ऊंचाई h की दीवार से नीचे कूद गया. जमीन पर पहुंचने से पहले उसने कितने एक भार का अनुभव किया?
(a) zero/शून्य
(b) W / 2
(c) W
(d) 2 W

Show Answer

Ans.(a)
Sol. Before he reach the ground he experienced a load of zero.

Q2. Who among the following first gave the experimental velocity of g ?
निम्नलिखित में से किसने पहले g का प्रयोगात्मक वेग दिया था?
(a) Cavendish /कैवेन्डिश
(b) Copernicus/ कोपरनिकस
(c) Brook Taylor/ ब्रुक टेलर
(d) none of these/ इनमे से कोई नहीं
Show Answer

Ans.(a)
Sol. The Cavendish experiment, performed in 1797–1798 by British scientist Henry Cavendish, was the first experiment to measure the force of gravity between masses in the laboratory and the first to yield accurate values for the gravitational constant.

Q3.When the planet comes nearer the sun moves
जब कोई ग्रह सूरज के निकट आता है तो वह किस प्रकार चलता है
(a) Fast/तेज
(b) Slow/धीरे
(c) Constant at every point/प्रत्येक बिंदु पर स्थिर
(d) None of the above/उपरोक्त में से कोई नहीं

Show Answer

Ans.(a)
Sol. A planet’s orbital speed changes, depending on how far it is from the Sun. The closer a planet is to the Sun, the stronger the Sun’s gravitational pull on it, and the faster the planet moves. The farther it is from the Sun, the weaker the Sun’s gravitational pull, and the slower it moves in its orbit.

Q4.Kepler’s second law regarding constancy of arial velocity of a planet is a consequence of the law of conservation of
ग्रह के एरियल वेग की दृढ़ता के संबंध में केप्लर का दूसरा नियम किसके संरक्षण के कानून का परिणाम है
(a) Energy/ ऊर्जा
(b) Angular momentum/ कोणीय गति
(c) Linear momentum/ रैखिय गति
(d) None of these/ इनमे से कोई नहीं

Show Answer

Ans.(b)
Sol. Kepler’s second law regarding constancy of arial velocity of a planet is a consequence of the law of conservation of Angular momentum.

Q5.The period of geostationary artificial satellite is
भूगर्भीय कृत्रिम उपग्रह की अवधि क्या है?
(a) 24 hours/ घंटे
(b) 6 hours/ घंटे
(c) 12 hours/ घंटे
(d) 48 hours/ घंटे

Show Answer

Ans.(a)
Sol. The period of geostationary artificial satellite is 24 hours.

Q6. Gravitational force is maximum at which of the following place?
निम्नलिखित में से किस स्थान पर गुरुत्वाकर्षण बल अधिकतम है?
(a) At equator/ भूमध्य रेखा पर
(b) At tropic of cancer/ कर्क के उष्णकटिबंधीय पर
(c) At tropic of Capricorn/ मकर राशि के उष्णकटिबंधीय पर
(d) At poles / ध्रुवों पर

Show Answer

Ans.(d)
Sol. The value of Gravitational Force range from a minimum of 9.78 metre per second squared at the Equator to a maximum of 9.83 metre per second squared at the poles. Hence Gravitational Force is maximum on polls.

Q7. There is no atmosphere on the moon because
चाँद पर कोई वातावरण नहीं है क्योंकि
(a) It is closer ot the earth/ यह पृथ्वी के करीब है
(b) It revolves round the earth/ यह पृथ्वी के चारों ओर घूमता है
(c) It gets light from the sun/ यह सूरज से प्रकाश प्राप्त करता है
(d) the value of escape velocity on the surface of the moon is small

Show Answer

Ans.(d)
Sol. Moon has no atmosphere because the value of acceleration due to gravity ‘g’ on surface of moon is small. Therefore, the value of escape velocity on the surface of the moon is small . The molecules of the atmospheric gases on the surface of the moon have thermal velocities greater than the escape velocity. That is why all the molecules of gases have escaped and there is no atmosphere on moon.

Q8. The dimensions of universal gravitational constant are
सार्वभौमिक गुरुत्वाकर्षण नियतांक का आयाम क्या हैं
(a) M^2 L^2 T^–2
(b) M^–1 L^3 T^–2
(c) M L^–1 T^–2
(d) M L^2 T^–2

Show Answer

Ans.(b)
Sol. Dimensional Formula of Universal Constant of Gravitation = M^–1 L^3 T^–2

Q9. If the radius of the earth were to shrink by one percent, its mass remaining the same, the acceleration due to gravity on the earth’s surface would
यदि पृथ्वी की त्रिज्या एक प्रतिशत कम हो जाती है, तो इसका द्रव्यमान समान रहता है, पृथ्वी की सतह पर गुरुत्वाकर्षण के कारण त्वरण कितना होगा?
(a) decrease/कम हो जाता है
(b) remains unchanged/अपरिवर्तित रहता है
(c) Increase/बढ़ जाता है
(d) None of these/इनमें से कोई नहीं

Show Answer

Ans.(c)
Sol. when the radius or the surface decreases, the depth of the earth gets near to the amplitude, it causes gravity to become nearer to the amplitude thus,the acceleration due to gravity increases.

Q10. What would be the duration of the year if the distance between the earth and the sun gets doubled?
यदि पृथ्वी और सूर्य के बीच की दूरी दोगुनी हो जाती है तो वर्ष की अवधि कितनी होगी?
(a) 1032 days
(b) 129 days
(c) 365 days
(d) 730 days

Show Answer

Ans.(a)
Sol. Kepler’s 3rd law –