HPSC Topic Wise MCQ Series: Physics-III

# HPSC Topic Wise MCQ Series: Physics-III

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## Physics Multiple Choice Questions For HCS Exam

### Important 20000 MCQ Series For HCS Exam: PHYSICS PART-III

Q1. The energy that can harness heat stored below the earth's surface is known as:

(a) thermal energy

(b) nuclear energy

(c) tidal energy

(d) geo-thermal energy

Ans: (d) geo-thermal energy

Explanation: Geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magm(a)

Q2. The temperature of boiling water in a steam engine may be high because:

(a) there are dissolved substances in water

(b) there is low pressure inside the boiler

(c) there is high pressure inside the boiler

(d) the fire is at very high temperature

Ans: (c) there is high pressure inside the boiler

Explanation:

The temperature of boiling water in a steam engine may be high because there is high pressure inside the boiler.

Q3. An instrument used to measure humidity is:

(a) Anemometer

(b) Hygrometer

(c) Thermometer

(d) Pyrheliometer

Ans: (b) Hygrometer

Explanation: A hygrometer is a weather instrument used to measure the amount of humidity in the atmosphere.

Q4. Fat can be separated from milk in a cream separator because of:

(a) Cohesive force

(b) Gravitational force

(c) Centripetal force

(d) Centrifugal force

Ans: (d) Centrifugal force

Explanation: When the milk is churned vigorously the cream from it is separated out duel the effect of centrifugal force as when liquids of different specific gravities revolve around the same distance and with the same angular velocity, then a huge centrifugal force is exerted on the heavier than on the lighter one.

Q5. A transformer works with

(a) alternating current only

(b) direct current only

(c) both AC and DC

(d) any signal

Ans: (a) alternating current only

Explanation:  ac changes with time, it produces a varying magnetic flux while flowing through the primary winding which induces emf in the secondary coil. The reason is that transformers work via induction of electrical forces by changes in magnetic fields, so the constant fields produced by dc currents won't work at all.

Q6. In the Earth, the weight of a body is maximum at the

(a) North Pole

(b) South Pole

(c) Equator

(d) Surface

Ans: (d) Surface

Explanation: The earth is not completely spherical, the maximum gravity of the earth acts on center of the earth or say surface. From center to pole's distance is less than equator, hence the weight of body on the earth's pole is greater than the earth's equator.

Q7. The technique of collecting information about an object from a distance without malting physical contact with it is

(a) Remote sensing

(b) Remote control

(c) Remote accessing

(d) Space shuttle

Ans: (a) Remote sensing

Explanation: Remote sensing is the process of detecting and monitoring the physical characteristics of an area by measuring its reflected and emitted radiation at a distance from the targeted are(a) Special cameras collect remotely sensed images of the Earth, which help researchers "sense" things about the Earth.

Q8. The head mirror used by ENT doctors is

(a) Concave

(b) Convex

(c) Plane

(d) Plano-convex

Ans: (a) Concave

Explanation:  A head mirror is mostly used for examination of the ear, nose & throat. It comprises a circular concave mirror, with a small hole in the middle, and is attached to a head ban(d)

Q9. Direct conversion of solar energy with the use. of a photo voltaic cell results in the production of

(a) Optical energy

(b) Electrical energy

(c) Thermal energy

(d) Mechanical energy

Ans:(b) Electrical energy

Explanation: A solar cell, or photovoltaic cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.

Q10. A man inside an artificial satellite feels weightlessness because the force of attraction due to earth is.

(a) zero at that place

(b) is balanced by the force of attraction due to moon

(c) equal to the centripetal force

(d) non-effective due to particular design of the satellite

Ans: (a) zero at that place

Explanation: You would feel weightless on any satellite, whether natural or artificial, as long as that satellite is too small to have significant gravity of its own. That’s because the satellite is falling, not straight down, and the force of attraction due to earth is zero at that place. But like a rock that you have thrown, in a curve. But the curve of its fall matches the curve of the planet it is falling toward, so it never hits it. Everything inside the satellite (if it’s hollow) or on it is also falling at the same speed, including the people, so they feel weightless.

If you fall off a building, you’ll feel weightless until you hit the ground.

Q11. A particle dropped from the top of a tower uniformly falls on ground at a distance which is equal to the height of tower. Which of the following paths will be traversed by the particle?

(a) Circle

(b) Parabolic

(c) Great circle

(d) Hyper-parabolic

Ans: (b) Parabolic

Explanation: If a particle is dropped from the top of a tower uniformly falls on ground at a distance which is equal to the height of tower then a parabolic path will be traversed by a particle because when the particle is dropped that point is called the point of projection and when it reaches the ground that point is called the point of impact. Now, if the two points are met with one another the curve emerges is parabolic in nature. Hence, we can say that the path followed by the particle is of parabolic trajectories.

Q12. Electron microscope was invented by

(a) Knoll and Ruska

(b) Robert Koch

(c) Leeuwenhoek

(d) C. P. Swanson

Ans: (a) Knoll and Ruska

Explanation: The invention of the electron microscope by Max Knoll and Ernst Ruska at the Berlin Technische Hochschule in 1931 finally overcame the barrier to higher resolution that had been imposed by the limitations of visible light.

Q13. When a bottle of scent is kept open in a comer of a room its odour is felt in all parts of the room. This is due to the phenomenon of:

(a) evaporation

(b) vaporization

(c) diffusion

(d) sublimation

Ans: (c) diffusion

Explanation: In the case of the perfume, perfume is very volatile. This means it easily changes from a liquid to a gas at room temperature. When you spray the perfume, tiny droplets of the liquid are atomized into the air where they quickly evaporate. The gas particles move randomly about, diffusing into surrounding air in the room, becoming more dilute as they spread out. Soon the entire room contains some of the perfume molecules. This is also true for the odor of a skunk, rotten eggs, and leaking natural gas.

Q14. Clear nights are colder than cloudy nights because of

(a) conduction

(b) condensation

(d) insolation

Explanation: This is true even during complete overcast conditions because the clouds are generally colder than the air at the ground. Thus clouds in effect reduce the radiation imbalance between the upward flux from the ground and downward flux from the atmosphere, relative to that on clear nights.

Q15. Speed of sound is the greatest in:

(a) Water

(b) Air

(c) Glass

(d) Glycerine

Ans: (c) Glass

Explanation:  sound travels faster in liquids than in gases and faster in solids than in liquids. The greater the elasticity and the lower the density, the faster sound travels in a medium. ... In air, for example, the speed of sound increases with an increase in temperature.

For air, the sound speed is about 330 m/s under ordinary conditions. Most typical glass materials end up with sound speeds of 2000 m/s to 6000 m/s, depending on both the type of glass and the type of sound.

Q16. A gas thermometer is more sensitive than a liquid thermometer because of a gas:

(a) is lighter than liquid

(b) expands more than a liquid

(c) is easy to obtain

(d) does not change state easily

Ans: (d) does not change state easily

Explanation: Gas thermometers are more sensitive because gas itself is, on average, more sensitive to changes in energy than liquids. That is to say, the same amount of energy will cause a greater amount of temperature change in a gas than in a liquid of the same substance. Temperature isn't "real" property, and neither is heat. Gas does not change its state easily.

Q17. Which one of the following is used for sunglasses?

(a) Pyrex glass

(b) Flint glass

(c) Crooks glass

(d) Crystal glass

Ans: (c) Crooks glass

Explanation: Crookes glass: In this glass mainly cerium oxide (CiO2) is present which sharply absorbs the ultraviolet rays from the sunlight so utilized in making lenses of eyeglasses.

Q18. The speed of light with the rise in the temperature of the medium:

(a) Increases

(b) Decreases

(c) Remains unaltered

(d) Drops suddenly

Ans: (c) Remains unaltered

Explanation: If we heat the object the particle within an object gets heat up moved in different directions due to temperature rise. But light has wave-particle duality so we can't say definitely it acts as a particle when interacting with the heat addition process. Besides it has very light mass even though it gets heat up there is no change in that momentum.

Q19. Clothes keep us warm in winter because they:

(a) supply heat

(b) do not radiate heat

(c) prevent air from contacting the body

(d) prevent the heat of the body from escaping

Ans: (d) prevent the heat of the body from escaping

Explanation:

Cotton clothes are thin and do not have space in which air can be trapped Thus, cotton clothes do not prevent heat coming out of our body. Woolen clothes keep us warm during winter because wool is a poor conductor of heat and it has air trapped in between the fibres and thus prevent the heat of the body from escaping.

Q20. In a refrigerator what produces the cooling?

(a) The ice which deposits on the freezer

(b) The sudden expansion of a compressed gas

(c) The evaporation of a volatile liquid

(d) None of these

Ans: (d) None of these

Explanation: It has a compressor that runs the refrigerant up to a high pressure. This causes the gas to both heat up and condense. Then there are cooling coils, typically on the back of the refrigerator, where the refrigerant is sent to cool down. ... Once the pressure is off, the liquid evaporates, becoming very col(d)

Q21. Why are we able to hear short wave broadcasts better than long wave broadcasts?

(a) Short waves are more energetic than long waves.

(b) Short waves are unaffected by atmospheric disturbances.

(d) By convention, short waves are meant for long distances, whereas long waves are reserved for short distances.

Ans: (a) Short waves are more energetic than long waves.

Explanation: Shortwave broadcasts are made by nearby radio stations. By convention, short waves are meant for long distances whereas long waves are reserved for short distances.

Q22. When the barometer reading dips suddenly, it is an indication of

(a) Hot weather

(b) Calm weather

(c) Storm

(d) Dry weather

Ans: (c) Storm

Explanation: If the reading is going down very fast then it's an indication of the storm (within 5-6 hours) otherwise a slow downfall of reading suggests a low-pressure area is passing in a nearby region, it may rain.

Q23. Good conductor of electricity is

(a) dry air

(b) paper

(c) kerosene

(d) graphite

Ans: (d) graphite

Explanation: Graphite is a good conductor of heat and electricity. This is because, like metals, graphite contains delocalized (free) electrons. The carbon-carbon bond allows for the free movement of electrons.

Q24. Which of the following is a non-renewable source of energy?

(a) Biogas

(b) Solar

(c) Wind

(d) Coal

Ans: (d) Coal

Explanation: All fossil fuels are nonrenewable, but not all nonrenewable energy sources are fossil fuels. Coal, crude oil, and natural gas are all considered fossil fuels because they were formed from the buried remains of plants and animals that lived millions of years ago.

Q25. Solar energy is converted into chemical energy during

(a) Transpiration

(b) Photosynthesis

(c) Diffusion

(d) Osmosis

Ans: (b) Photosynthesis

Explanation: Photosynthesis in plants converts solar energy into chemical energy using electrons and protons from water. The process of photosynthesis in plants involves a series of steps and reactions that use solar energy, water, and carbon dioxide to produce organic compounds and oxygen.