Important MCQs on Physics for HCS

# Important MCQs on Physics for HCS

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# Important MCQs on Physics for HCS

Physics is one of the most important parts of General Science. This subject has its importance as far as Science and Technology is concerned. The concepts of Physics forms the basis to learn and understand various new technologies emerging one after the other. This is the reason that questions from basic physics have become popular in various Civil services Exams. In the present article, you will find some of the most Important MCQs on Physics for HCS and other State Civil Services Exams covering various important topics.

Q1. Which of the following is used in powdered form as a lubricant?

(a) Graphite
(b) Chalk
(c) Salt
(d) Sugar

Ans: (a) Graphite

Explanation:

Dry lubricants or solid lubricants are materials that, despite being in the solid phase, can reduce friction between two surfaces sliding against each other without the need for a liquid oil medium.

The two main dry lubricants are graphite and molybdenum disulfide. They offer lubrication at temperatures higher than liquid and oil-based lubricants operate. Dry lubricants are often used in applications such as locks or dry lubricated bearings.

Q2. The complete form of ‘IC’ in electronics is-

(a) Internal circuit

(b) Independent circuit

(c) Integrated circuit

(d) Inbuilt circuit

Ans: (c) Integrated circuit

Explanation:

Integrated Circuit (IC), chip or microchip, is a miniaturized electronic circuit consisting of multiple electronic components interconnected to form a complete electronic function. It is manufactured on the surface of a thin substrate of semiconductor material.

Q3. What is the advantage of the parallel connection of circuits?

(a) Same voltage is available

(b) All appliances get fused

(c) Fluctuation

(d) All of the above

Ans: (a) Same voltage is available

Explanation:

One of the advantages of parallel circuits is that they ensure all components in the circuit have the same voltage as the source. For instance, all bulbs in a string of lights have the same brightness.

Q4. Fluid friction is also known as ___________.

(a) Rolling friction
(b) Sliding friction
(c) Drag
(d) Static friction

Ans.  (c) Drag

Explanation:

In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving concerning a surrounding fluid.

Q5. Spring tides occur when ______.

(a) the moon, the sun, and the earth are in the same line

(b) the sun is closest to earth

(c) the moon is farthest from earth

(d) the earth is at right angles with the sun and the moon

Ans. (a) the moon, the sun, and the earth are in the same line

Explanation:

Spring tides are especially strong tides (they do not have anything to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon.

Read also: HCS MCQ Series: Physics Part 1

Q6. Name the instrument used for listening to the sound produced within the human body?

(a) manometer

(b) Stethoscope

(c) pyrometer

(d) None of these

Ans.  (b) Stethoscope

Explanation:

Stethoscope, a medical instrument used in listening to sounds produced within the body, chiefly in the heart or lungs. It was invented by the French physician R.T.H.

Q7. 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) geothermal energy

Ans: (d) geothermal 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 magma.

Q8. 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.

Q9. 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 outduel 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.

Q10. The technique of collecting information about an object from a distance without making 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 area Special cameras collect remotely sensed images of the Earth, which help researchers "sense" things about the Earth.

Read also: HCS MCQ Series: Physics Part 2

Q11. Doppler's effect is related to:

(a) change in wavelength of sound

(b) change in amplitude of the sound

(c) change in frequency of sound

(d) change in wave velocity of time

Ans. (c) change in frequency of sound

Explanation:

The Doppler effect (or the Doppler shift) is the change in frequency of a wave about an observer who is moving relative to the wave source. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increase in the frequency.

Q12. The magnetic effect of current gives rise to which force?

(a) Mechanical

(b) Spring

(c) Friction

(d) Gravitational

Ans. (a) Mechanical

Explanation:

Since a current-carrying wire was able to deflect a compass needle, it was concluded that a current flowing in a wire always gives rise to a magnetic field around it. The importance of the magnetic effects of current lies in the fact that it gives rise to mechanical forces.

Q13.  The motion of a train is an example of which kind of motion?

(a) Rotatory motion

(b) Spin motion

(c) Projectile motion

(d) Translatory motion

Ans. (d) Translatory motion

Explanation:

The motion in which every point on the moving body moves through the same distance in the same interval of time is called Translatory motion.

Translatory motion are of two types - Rectilinear motion and Curvilinear motion

Examples of rectilinear motion are – A train moving on a straight rail track, a freely falling stone, a coin moving over a carrom board, etc.

Q14. Through which light cannot pass?

(a) Notebook paper

(b) Water

(c) Book

(d) Sunglasses

Ans. (c) Book

Explanation:

An opaque object is neither transparent (allowing all light to pass through) nor translucent (allowing some light to pass through). When light strikes an interface between two substances, in general, some may be reflected, some absorbed, some scattered, and the rest transmitted (also see refraction).

Q15. 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 headband.

Read also: HCS MCQ Series: Physics Part 3

Q16. 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 the moon

(c) equal to the centripetal force

(d) non-effective due to the 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.

Q17. 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 the 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.

Q18. The energy that generates wind comes from what source?

(a) Anemometers

(c) Ocean currents

(d) None of the above

Explanation:

The wind is nothing but the form of moving air. It is caused by the uneven heating of the earth's surface by the sun. Hence, the energy that generates wind comes from solar radiation.

Q19. An electric fuse is based on-

(a) the chemical effect of the current

(b) the magnetic effect of the current

(c) the heating effect of the current

(d) All of the above

Ans. (c) the heating effect of the current

Explanation:

The electric fuse is based on the heating effect of the current. electric fuse has a low melting point so when high current flow through fuse wire is heated and melted and break down the electric circuit.

Q20. On which of the following techniques photo state machine works?

(a) Magnetic Imager Making

(b) Thermal Image-Making

(c) Electrostatic Image-Making

(d) Electromagnetic Image-Making

Ans. (c) Electrostatic Image-Making

Explanation:

All Electrostatic Copiers work under the premise that a charge of electricity is placed on an Image Drum which can retain the electric charge much like a capacitor holds its charge but with the ability to hold or release the charge depending on how much light and darkness is applied to the Image Drum. A photocopier (also known as a copier or copy machine) is a machine that makes paper copies of documents and other visual images quickly and cheaply. Most current photocopiers use a technology called xerography, a dry process using heat. Copiers can also use other technologies such as inkjet, but xerography is standard for office copying.

Read also: Biology Questions for HPSC HCS Exam

Q21. The device that confirms the presence of electric charge:

(a) Electric Meter

(b) Electro Meter

(c) Electron Microscope

(d) Electroscope

Ans. (d) Electroscope

Explanation:

An electroscope is an early scientific instrument used to detect the presence of an electric charge on a body. It detects charge by the movement of a test object due to the Coulomb electrostatic force on it. The amount of charge on an object is proportional to its voltage.

Q22. In the conventional direction of current flow the particles considered to be moving are:

(a) Protons

(b) Electrons

(c) Atoms

(d) Ions

Ans. (b) Electrons

Explanation:

The particles that carry charge through wires in a circuit are mobile electrons. The electric field direction within a circuit is by definition the direction that positive test charges are pushed. Thus, these negatively charged electrons move in the direction opposite the electric field.

Q23. The theory on which magnetism is explained-

(a) Domain theory

(b) Electric theory

(c) Kepler’s theory

(d) Polar theory

Ans. (a) Domain theory
Explanation:

A more modern theory of magnetism is based on the electron spin principle. From the study of atomic structure, it is known that all matter is composed of vast quantities of atoms, each atom containing one or more orbital electrons.

Q24. Clothes keep us warm in winter because they:

(a) supply 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 cloths do not prevent heat from coming out of our bodies. Woolen clothes keep us warm during winter because wool is a poor conductor of heat and it has air trapped in between the fibers and thus prevents the heat of the body from escaping.

Q25. Why are we able to hear shortwave 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.

Q26. Which of the following parts of the sunlight makes the solar cooker hot?

(a) Ultra violet

(b) Red light

(c) Infrared

(d) Cosmic rays

Ans: (c) Infrared

Explanation:

A solar cooker lets the UV light rays in and then converts them to longer infrared light rays that cannot escape. An effective solar cooker will use the energy of the sun to heat a cooking vessel and efficiently retain the energy (heat) for maximum cooking effectiveness.

Q27. The commercial unit of electrical energy is-

(a) Volt

(b) Watt

(c) Kilowatt

(d) Kilowatt-hour

Ans. (d) Kilowatt-hour

Explanation:

Kilowatt-hour is the commercial unit of electrical energy. We have seen that power is the rate of energy consumed or delivered. If 1 joule of energy is used per second, we say that energy is used at the rate of 1 watt.

Q28. How much electric potential does the live wire carry?

(a) 100 volts

(b) 150 volts

(c) 185 volts

(d) 220 volts

Ans. (d) 220 volts

Explanation:

The wire(normally red color) that is connected to the phase conductor is called the phase wire or live wire because it has a potential of 220 volts and gives a shock when touched with a bare hand.

Q29. Above which level of noise is a cause of hearing loss and damage?

(a) Approx 80 decibels

(b) Approx 130 decibels

(c) Approx 150 decibels

(d) Approx 180 decibels

Ans. (d) Approx 180 decibels
Explanation:

A healthy person hears all sound frequencies from approximately 20 to 20,000 Hz

Pain = 140dB

Discomfort = 120 dB

Jack hammers and Rock concerts = 110dB

Industrial noise = 90dB

Normal conversation = 60dB

Q30. What is the force of attraction between any two bodies by virtue of their masses is called?

(a) Electromagnetic Force

(b) Gravitational Force

(c) Centripetal Force

(d) Nuclear Force

Ans. (b) Gravitational Force

Explanation:

Gravitational Force is the force of attraction between any two bodies by virtue of their masses. It is a universal force and every object in the universe experiences a gravitational force due to every other object.

Q31. The instrument which uses sound waves to measure the depth of oceans is

(b) Sonar

(c) Altimeter

(d) Venturimeter

Ans. (b)

Explanation:

Sonar devices are used to measure the depth of the sea. A sound is sent out and the echo monitored We know the speed of sound in water.

Q32. The best conductor of heat among the following is-

(a) alcohol

(b) mercury

(c) ether

(d) water

Ans. (b)

Explanation:

Like all metals, mercury is an excellent conductor of heat. This is one of the reasons why mercury is used in a traditional mercury thermometer.

Q33. What principle/law explains the working of the hydraulic brakes in automobiles?

(a) Bernoulli's law

(b) Poiseuille's principle

(c) Pascal's law

(d) Archimedes' principle

Ans. (c)

Explanation:

Pascal's law states that when there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container.

Hydraulic systems use an incompressible fluid, to transmit forces from one location to another within the fluid. Most aircraft use hydraulics in the braking systems and landing gear.

Q34. Which set of conditions represents the easiest way to liquefy a gas?

(a) Low temperature and high pressure

(b) High temperature and low pressure

(c) Low temperature and low pressure

(d) High temperature and high pressure

Ans. (a)

Explanation:

Gases can be liquefied by one of three general methods:

1. By compressing the gas at temperatures less than its critical temperature;
2. By making the gas do some kind of work against an external force, causing the gas to lose energy and change to the liquid state;
3. By using the Joule-Thomson effect

Joule-Thomson effect, the gas is first pumped into a container under high pressure. The container is fitted with a valve with a very small opening. When the valve is opened, the gas escapes from the container and expands quickly. At the same time, its temperature drops.

Q35. The substance which conducts current in the solid-state is-

(a) diamond

(b) graphite

(c) iodine

(d) sodium chloride

Ans. (b)

Explanation:

All solid metals have some conductive properties with gold and copper being among some of the best. Some non-metallic materials can also conduct electricity in solid forms, such as graphite and silicon. Compounds of metals do not conduct electricity as a solid, but metals are good conductors of electricity.

Q36. Which one of the following has ‘ohm’ as its unit?

(a) Resistivity

(b) Conductivity

(c) Conductance

(d) Inductive Reactance

Ans. (d) Inductive Reactance

Explanation:

The unit of Inductive Reactance is ‘ohm’. Inductive Reactance = Angular frequency x Inductance Inductive reactance is defined as the opposition to changing current flow. It is measured in ohm. Any changing current in an inductor will be impeded because of the inductance associated with it.

Q37. What is the value of the Triple point of water?

(a) 273.16 K

(b) 273.16° C

(c) 0° C

(d) -273.16 K

Ans.  (a) 273.16 K
Explanation:

The triple point of water is the temperature at which ice, water, and water vapors coexist. The value of the Triple point of water is 273.16 K Kelvin is the S.I unit of Temperature represented by symbol K.

T 3 = 273.1K This is equivalent to 0.01 o C and 32.02 o F

Q38. The magnet is strongest near the-

(a) on equator point from the poles of the magnet
(b) ends of the magnet
(c) center of magnet
(d) None of the above

Ans. (b) ends of the magnet

Explanation:

The magnetic field of a bar magnet is strongest at either pole of the magnet. It is equally strong at the north pole when compared with the south pole. The force is weaker in the middle of the magnet and halfway between the pole and the center.

Q39. The property of the human eye for seeing near objects and distant object is called-

(a)Myopia

(b)Accommodation

(c)Presbyopia

(d)Correction

Ans. (b) Accommodation

Explanation:

Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies.

Q40. A washing machine works on the principle of-

(a) Diffusion

(b) Dialysis

(c) Centrifugation

(d) Both B and C

Ans. (c) Centrifugation

Explanation:

The washing machine works on the principle of both laws of physics namely centripetal and centrifugal force. The Wash cycle undergoes centrifugal force wherein the force goes from inside to outside thoroughly making sure every cloth is soaked in soapy water, here water with soap will undergo centrifugal force.