Railway 2018 Previous Year GK Questions with Answers

The correct answer is C, 500 W. The work done against gravity is mgh = 40 × 10 × 5 = 2000 joule, and power is work divided by time, so 2000 ÷ 4 = 500 watt.

Power is the rate of doing work, measured in watt, where one watt is one joule per second. In climbing stairs the useful work is the gain in potential energy, mgh, where only the vertical rise counts and the length of the staircase does not matter. If the same girl ran up in 2 seconds the work would be the same 2000 joule but the power would double to 1000 watt, which shows that power depends on how fast the work is done.

Option A is wrong because 100 W comes from dividing by the wrong quantity. Option B is wrong because 200 W would need 10 seconds. Option D is wrong because 2000 is the work in joule, not the power in watt.

Exam tip: work = mgh, power = work ÷ time, and one horsepower is about 746 watt.

The correct answer is C, zero. Constant velocity means no acceleration, and by Newton's second law force equals mass into acceleration, so the net force must be zero.

Newton's first law says a body continues in its state of rest or of uniform motion in a straight line unless an external force acts on it, which is why motion at a steady speed in a fixed direction needs no force to keep it going. Force is needed only to change the speed or the direction. A car moving at a steady 60 km per hour on a straight road is in the same state: the engine's push only balances friction and air resistance, so the forces cancel and the net force is zero. Such a body is said to be in equilibrium.

Options A, B and D are wrong because any net force in a direction would produce acceleration and so change the velocity, which contradicts the given condition of constant velocity.

Exam tip: constant velocity means zero acceleration and therefore zero net force, not zero force at all.

The correct answer is B, Platinum. Platinum is the least reactive of the four, so it is found in nature in the free or native state as the metal itself.

A metal occurs free only when it does not react with the air, water and other substances around it. In the reactivity series the metals at the bottom - gold, platinum and silver - are called noble metals and are found native; those higher up occur as oxides, sulphides or carbonates and must be extracted from their ores. This is why gold nuggets are found in river sand while aluminium has to be won from bauxite by electrolysis.

Option A is wrong because copper is mostly mined as copper pyrites and other ores, though small native deposits do exist. Option C is wrong because iron is always found as an oxide such as haematite or magnetite. Option D is wrong because potassium is so reactive that it burns on contact with water and is never found free.

Exam tip: gold, platinum and silver occur native; the more reactive a metal, the more firmly it stays locked in its ore.

The correct answer is C, Manipur. M. C. Mary Kom was born in Kangathei village of Churachandpur district in Manipur.

Mary Kom is the only woman boxer to have won six world championship titles, and she is nicknamed Magnificent Mary. She took the bronze medal in the flyweight class at the London Olympics of 2012, the first Indian woman boxer to win an Olympic medal, and she has also won gold at the Asian Games of 2014 and the Commonwealth Games of 2018. She received the Arjuna Award, the Padma Shri, the Rajiv Gandhi Khel Ratna and the Padma Vibhushan, and served as a nominated member of the Rajya Sabha.

Option A is wrong because Mizoram is best known in Indian sport for footballers. Option B is wrong because Assam is the home state of the boxer Shiva Thapa and the sprinter Hima Das. Option D is wrong because Meghalaya has produced no boxer of this record.

Exam tip: Mary Kom of Manipur, six world titles, bronze at London 2012, called Magnificent Mary.

The correct answer is D, Intermolecular forces are weak. Melting and boiling only have to break the weak forces between the molecules, not the strong bonds inside them, so little heat is needed.

A covalent bond is formed by the sharing of electrons and is itself strong, but it acts only within the molecule. Separate molecules are held to one another by weak van der Waals forces, and these give way at low temperature, which is why water, ammonia, carbon dioxide and most organic compounds melt and boil easily. Ionic compounds such as sodium chloride behave in the opposite way: a strong electrostatic force runs through the whole crystal, so their melting points are very high. Giant covalent solids like diamond and silicon carbide are the exception, since their bonds form a continuous network.

Options A, B and C are wrong because they all claim the forces between molecules are medium or strong, which would raise the melting and boiling points instead of lowering them.

Exam tip: strong bond inside the molecule, weak force between molecules, so covalent compounds melt at low temperature.

The correct answer is C, 24 J. By the work-energy theorem the work done equals the change in kinetic energy, which is half of 1.0 into 8 squared minus 4 squared, that is 0.5 × (64 - 16) = 24 joule.

Kinetic energy is given by half m v squared, so at 4 m/s the object has 8 joule and at 8 m/s it has 32 joule; the force must supply the difference of 24 joule. Note that doubling the speed makes the kinetic energy four times, because the speed is squared. The work-energy theorem holds whatever the path taken, which is why the question can be solved without knowing the force or the distance.

Option A is wrong because 8 joule is only the starting kinetic energy. Option B is wrong because 32 joule is the final kinetic energy, not the change. Option D is wrong because 16 joule comes from taking half of the difference of the squares of the speeds incorrectly.

Exam tip: work done = final kinetic energy minus initial kinetic energy, and doubling speed makes kinetic energy four times.

The correct answer is D, Lead and tin. Solder is an alloy of lead and tin, usually in nearly equal parts.

An alloy is a mixture of a metal with one or more other elements, made to gain a property the pure metal lacks. Solder is useful because the mixture melts at a far lower temperature than either lead or tin alone, so it flows easily and is used to join wires and electrical joints. Other alloys asked in papers are brass, made of copper and zinc, bronze of copper and tin, stainless steel of iron, chromium and nickel, and German silver of copper, zinc and nickel.

Option A is wrong because lead with copper is not the soldering alloy. Option B is wrong because tin with iron gives tin plating, used for tin cans. Option C is wrong because lead and iron together are not used as solder.

Exam tip: solder is lead plus tin and melts at a low temperature; brass is copper and zinc, bronze is copper and tin.

The correct answer is D, Madhya Pradesh. The Bansagar Dam stands on the Sone river in the Shahdol region of Madhya Pradesh.

Bansagar is a joint project of Madhya Pradesh, Uttar Pradesh and Bihar, the three states through which the Sone flows, and it serves both irrigation and power. The Sone is a major right bank tributary of the Ganga; it rises near Amarkantak, the same highland that gives birth to the Narmada, and joins the Ganga near Patna. The dam is named after the sage Bana, who is linked in tradition with the Sone valley.

Option A is wrong because Maharashtra has Koyna and Jayakwadi. Option B is wrong because Gujarat has the Sardar Sarovar on the Narmada and Ukai on the Tapi. Option C is wrong because Andhra Pradesh has Nagarjuna Sagar and Srisailam on the Krishna.

Exam tip: Bansagar on the Sone in Madhya Pradesh, shared with Uttar Pradesh and Bihar; Amarkantak is the source of both the Narmada and the Sone.

The correct answer is C, Kesari. Bal Gangadhar Tilak started Kesari in 1881 and used it to carry the message of swaraj to Marathi readers.

Tilak brought out two papers from Pune in the same year, Kesari in Marathi and Maratha in English. His writings in Kesari on the Bengal partition and on the Muzaffarpur bomb case led to a charge of sedition, and in 1908 he was sentenced to six years of transportation to Mandalay in Burma. It was Tilak who declared that swaraj is my birthright and I shall have it, and he began the public Ganapati and Shivaji festivals to reach ordinary people.

Option A is wrong because Yugantar was started in Bengali by Barindra Kumar Ghosh and Bhupendranath Datta. Option B is wrong because the Bengalee was edited by Surendranath Banerjee. Option D is wrong because Amrita Bazar Patrika was founded by Sisir Kumar Ghosh and Motilal Ghosh.

Exam tip: Tilak - Kesari in Marathi and Maratha in English; Gandhi - Young India and Navajivan.

The correct answer is B, USA. The World Bank has its headquarters at Washington DC in the United States of America.

The World Bank and the International Monetary Fund were both set up after the Bretton Woods conference of 1944 and began work in 1945, and both have their offices in Washington DC. The Bank lends for long-term development - roads, power, irrigation, schools and health - while the IMF looks after exchange rates and short-term balance of payments trouble. The World Bank Group has five arms, of which the IBRD and the IDA together form the World Bank, and India was a founder member.

Option A is wrong because London holds the Commonwealth Secretariat and the International Maritime Organisation, not the World Bank. Option C is wrong because Tokyo is the seat of the United Nations University, while the Asian Development Bank is at Manila. Option D is wrong because Moscow hosts no such global lender.

Exam tip: World Bank and IMF at Washington DC, WTO at Geneva, ADB at Manila.

The correct answer is D, uterus. The zygote divides as it travels down the fallopian tube and the resulting ball of cells gets implanted in the thick lining of the uterus.

Fertilisation itself takes place in the fallopian tube, where a sperm fuses with the ovum to form the zygote. Repeated division turns it into an embryo, which reaches the uterus in about a week and sinks into the endometrium, the soft inner wall prepared by hormones. There the placenta develops and supplies the growing embryo with food and oxygen from the mother's blood while carrying away waste. Human pregnancy lasts about nine months.

Option A is wrong because the cervix is only the narrow neck of the uterus that opens into the vagina. Option B is wrong because the ovary produces the ovum and hormones but does not hold the embryo. Option C is wrong because the vagina is the passage that receives the sperm and later serves as the birth canal.

Exam tip: fertilisation in the fallopian tube, implantation in the uterus, nourishment through the placenta.

The correct answer is C, Mughal. Humayun's Tomb in Delhi is one of the earliest and finest examples of Mughal architecture.

The tomb was built in 1570 on the orders of Humayun's widow Bega Begum, also called Haji Begum, and the architect was Mirak Mirza Ghiyas of Persia. It was the first garden tomb in India, set in a charbagh, the four-part garden divided by water channels, and the first large structure to use red sandstone with white marble inlay and a high double dome. This plan became the model for the Taj Mahal built about eighty years later. UNESCO placed the tomb on the World Heritage list in 1993.

Option A is wrong because British architecture in India belongs to the colonial period after the eighteenth century. Option B is wrong because Chola architecture means Dravidian temples such as the Brihadeshwara temple at Thanjavur. Option D is wrong because Magadha is an ancient kingdom, not a style of tomb building.

Exam tip: Humayun's Tomb is the first garden tomb of India and the model for the Taj Mahal.

The correct answer is B, 19.8 × 10⁶ J. One kilowatt hour is 3.6 × 10⁶ joule, so 5.5 kWh = 5.5 × 3.6 × 10⁶ = 19.8 × 10⁶ joule.

The kilowatt hour is the commercial unit of electrical energy, the unit in which the electricity board bills a house, and it is often called one unit of electricity. It comes from energy = power × time, so one kilowatt of power drawn for one hour means 1000 watt × 3600 second = 3600000 joule. The joule is the SI unit of energy, and one watt is one joule per second.

Option A is wrong because 14.0 × 10⁶ J is about 3.9 kWh. Option C is wrong because 14.4 × 10⁸ J would be 400 kWh, a hundred times too large. Option D is wrong because 14.4 × 10⁵ J is only 0.4 kWh.

Exam tip: 1 kWh = 3.6 × 10⁶ J = one unit of electricity; multiply the number of units by 3.6 million to get joule.

The correct answer is B, Kinetic energy + Potential energy. The mechanical energy of a body is the sum of the energy of its motion and the energy of its position. Kinetic energy is half m v squared and gravitational potential energy is mgh, and their total stays the same as long as only gravity acts and friction is absent. That is the law of conservation of mechanical energy: a ball thrown upward loses kinetic energy and gains exactly as much potential energy, and a falling ball does the reverse, which is why a simple pendulum keeps swinging between the same two heights. When friction or air resistance acts, part of the mechanical energy turns into heat and sound, so it is no longer conserved, although the total energy of the system still is. Option A is wrong because chemical energy is stored in the bonds of fuels and food. Option C is wrong because heat is the energy of random molecular motion and is counted separately. Option D is wrong because electrical energy comes from moving charges. Exam tip: mechanical energy equals KE plus PE, and it stays constant only when no friction acts.

The correct answer is B, kinetic energy. A stretched bow stores elastic potential energy, and when the string is released that store becomes the kinetic energy of the flying arrow. Potential energy is the energy held by a body because of its position or its shape. Pulling the string changes the shape of the bow, so the work done by the archer is stored as elastic potential energy, the same kind of store found in a compressed spring or a wound watch spring. On release the bow springs back to its old shape and pushes the arrow forward, so the stored energy turns into energy of motion. A small part does escape as the twang of sound and as heat, but the main change is potential to kinetic. Option A is wrong because chemical energy is stored in the bonds of fuels and food, not in a bent bow. Option C is wrong because the sound is only a small loss, not the main conversion. Option D is wrong because heat is likewise a minor loss here. Exam tip: a stretched bow, a compressed spring and a drawn catapult all store elastic potential energy.

The correct answer is C, 240 J. Work done against gravity is weight multiplied by height, so 120 × 2 = 240 joules. Work is done when a force moves a body along the direction of that force, and it is measured as W = F × s. Here the boy must at least match the weight of the box, which is 120 N, and he moves it through 2 m, so the work done is 240 J. This work is stored in the box as gravitational potential energy, and the box would give back the same 240 J if it fell to where it started. Note that the weight is already given in newtons, so there is no need to multiply by g again. Option A is wrong because 60 J divides the weight by the height instead of multiplying. Option B is wrong because 120 J is only the weight in newtons, with the height left out. Option D is wrong because 130 J matches no step of the calculation. Exam tip: W = F × s, and work done against gravity is mgh, where mg is the weight.

The correct answer is A, 6.67 m/s². Find each mass from F = ma, add the masses, then divide the same force by the total. The first block gives m1 = 5 ÷ 10 = 0.5 kg and the second gives m2 = 5 ÷ 20 = 0.25 kg. Tied together they move as one body of mass 0.5 + 0.25 = 0.75 kg, and the same 5 N force now produces an acceleration of 5 ÷ 0.75, which is about 6.67 m/s². The joint acceleration is always less than the smaller of the two single accelerations, because the same push has to move more mass. Option B is wrong because 1.67 m/s² matches no step of this working. Option C is wrong because 5.67 m/s² would need a total mass of about 0.88 kg. Option D is wrong because 4.67 m/s² would need a total mass of about 1.07 kg. Exam tip: for one force on tied blocks the reciprocals add, that is 1 by a equals 1 by a1 plus 1 by a2.

The correct answer is A, 275 J. Kinetic energy is half m v squared, so half of 22 multiplied by 5 multiplied by 5 gives 275 joules. Kinetic energy is the energy a body has because of its motion. It rises in direct proportion to the mass but with the square of the speed, so doubling the speed makes the energy four times larger, which is why a fast vehicle needs a much longer distance to stop than a slow one. The joule is the SI unit of energy and equals one newton metre; one joule is the work done when a force of one newton moves a body through one metre. Option B is wrong because 110 J is mass multiplied by speed, which gives momentum, not energy, and in different units. Option C is wrong because 1100 J leaves out the half in the formula, that is it works out m v squared. Option D is wrong because 2750 J is ten times the correct value. Exam tip: write half m v squared carefully, because the half and the squared speed are where marks are usually lost.

The correct answer is B, 0 J. The body is thrown up at 20 m/s and gravity takes away 10 m/s of speed every second, so after 2 seconds its speed is zero. Using v = u − gt, we get v = 20 − 10 × 2 = 0 m/s. Kinetic energy is half m v squared, and with v = 0 the kinetic energy is also zero. At that instant the body is at the highest point of its path and all of its energy is potential energy, mgh = 2 × 10 × 20 = 400 J, since the body has risen 20 m. A moment later it begins to fall and the kinetic energy grows again. Option A is wrong because 100 J needs a speed of 10 m/s, which the body has after only one second. Option C is wrong because 400 J is the kinetic energy at the moment of throwing, and the potential energy at the top. Option D is wrong because 200 J matches no point of this motion. Exam tip: at the highest point of a vertical throw the speed, and so the kinetic energy, is zero.

The correct answer is A, Liquid. At normal atmospheric pressure water stays liquid between 0 °C and 100 °C, and 12 °C lies inside that range. Water freezes into ice at 0 °C, which is its melting point, and boils into steam at 100 °C, which is its boiling point, when the pressure is one atmosphere. Between these two fixed points the molecules have enough energy to slide over one another but not enough to fly apart, so water flows and takes the shape of its container while keeping a fixed volume. Water does evaporate slowly at 12 °C from an open surface, but that happens only at the top layer and does not change the state of the water below. Option B is wrong because ionic is not a state of matter at all; it describes a kind of bond or compound. Option C is wrong because water becomes a gas, that is steam, only above 100 °C. Option D is wrong because water turns solid only at or below 0 °C. Exam tip: remember 0 °C and 100 °C as the fixed points of water at one atmosphere.