Class 11 Physics MCQs | Chapter 1 Physical World – Part 1 (NCERT/CBSE)

Correct Answer: To understand the laws of nature and their interrelationships

Explanation: The primary objective of physics is to gain a deep understanding of the fundamental laws of nature and the relationships between different physical phenomena. By comprehending these laws, physicists can explain how the universe behaves at the most basic level, from subatomic particles to the largest galaxies.

Correct Answer: Kilogram

Explanation: In the International System of Units (SI), the kilogram is the fundamental unit of mass. The meter is the unit of length, and the second is the unit of time. Fundamental units are the building blocks of the SI system and are used to define all other units of measurement.

Correct Answer: Candela

Explanation: The SI unit of luminous intensity is the candela, which measures the perceived power of light emitted in a specific direction. It is one of the seven fundamental SI units and is crucial in fields like lighting, photography, and astronomy, where understanding light’s behavior and intensity is essential.

Correct Answer: Mechanics

Explanation: Mechanics is the branch of physics that deals with the study of motion, forces, and energy of objects. It encompasses two main subfields: kinematics, which describes motion without considering its causes, and dynamics, which focuses on the forces and their effects on motion.

Correct Answer: Johannes Kepler

Explanation: Johannes Kepler proposed the laws of planetary motion in the early 17th century. These laws describe the motion of planets around the Sun based on empirical observations and laid the foundation for modern celestial mechanics.

Correct Answer: Newton

Explanation: The newton (symbol: N) is a derived unit in the SI system, representing the amount of force required to accelerate a one-kilogram mass by one meter per second squared. Derived units are formed by combining fundamental units through mathematical expressions.

Correct Answer: Coulomb

Explanation: The SI unit of electric charge is the coulomb (symbol: C). It is defined as the charge transported by a constant current of one ampere in one second. Electric charge is a fundamental property of matter and plays a crucial role in electromagnetism.

Correct Answer: Albert Einstein

Explanation: Albert Einstein formulated the theory of relativity, which revolutionized the understanding of space, time, and gravity. His theories, especially the special and general theories of relativity, are fundamental to modern physics and cosmology.

Correct Answer: Hertz

Explanation: The SI unit of frequency is the hertz (symbol: Hz), which measures the number of cycles per second of a periodic phenomenon. It is commonly used to express frequencies of electromagnetic waves, sound waves, and other periodic oscillations.

Correct Answer: Gravitational force

Explanation: Gravitational force is one of the four fundamental forces in nature, alongside electromagnetism, strong nuclear force, and weak nuclear force. It is responsible for the attraction between masses and plays a crucial role in the structure of the universe.

Correct Answer: A systematic approach to observe, experiment, and analyze to understand natural phenomena

Explanation: The scientific method is a systematic approach used by scientists to investigate natural phenomena, formulate hypotheses, conduct experiments, and draw conclusions based on empirical evidence. It involves observation, hypothesis formation, experimentation, and analysis.

Correct Answer: Joule

Explanation: The joule (symbol: J) is the SI unit of energy. It is defined as the work done when applying a force of one newton over a distance of one meter. Energy is a fundamental concept in physics, encompassing various forms such as kinetic energy, potential energy, and thermal energy.

Correct Answer: Michael Faraday

Explanation: Michael Faraday discovered electromagnetic induction in the early 19th century. His experiments demonstrated that a changing magnetic field could induce an electric current in a nearby conductor, laying the foundation for electric generators and transformers.

Correct Answer: Volt

Explanation: The volt (symbol: V) is the SI unit of electric potential difference, also known as voltage. It represents the potential energy per unit charge between two points in an electric field. Voltage is crucial in understanding and measuring electric circuits and devices.

Correct Answer: Velocity

Explanation: Velocity is a vector quantity because it has both magnitude and direction. Scalar quantities, such as mass, temperature, and distance, are described solely by their magnitude and do not have a direction associated with them.

Correct Answer: Watt

Explanation: The watt (symbol: W) is the SI unit of power, representing the rate at which work is done or energy is transferred or transformed. It is defined as one joule per second and is commonly used to quantify the power of electrical devices, engines, and other energy sources.

Correct Answer: Isaac Newton

Explanation: Isaac Newton formulated the laws of motion in his work “Philosophiæ Naturalis Principia Mathematica” published in 1687. These laws describe the relationship between the motion of an object and the forces acting on it, laying the foundation for classical mechanics.

Correct Answer: Weber

Explanation: The weber (symbol: Wb) is the SI unit of magnetic flux, measuring the amount of magnetic field passing through a surface. It is a derived unit based on the tesla (unit of magnetic field strength) and the square meter (unit of area).

Correct Answer: Law of Conservation of Energy

Explanation: The Law of Conservation of Energy states that energy cannot be created or destroyed in an isolated system; it can only change forms. This principle is fundamental in physics and underpins many natural processes and technological applications.

Correct Answer: Force

Explanation: Force is a derived quantity in the SI system, defined as mass times acceleration (F = ma). The base quantities in SI are length, mass, time, electric current, temperature, amount of substance, and luminous intensity.

Correct Answer: The study of matter and energy and their interactions in the universe

Explanation: Physics is the branch of science that deals with the study of matter, energy, and their interactions in the universe. It aims to understand the fundamental laws governing natural phenomena and to explain the behavior of everything from subatomic particles to galaxies.

Correct Answer: Biology

Explanation: Biology is not a branch of physics; it is a separate scientific discipline that focuses on the study of living organisms and their interactions. The major branches of physics include mechanics, optics, thermodynamics, electromagnetism, and quantum mechanics.

Correct Answer: Albert Einstein

Explanation: Albert Einstein is often regarded as the father of modern physics due to his groundbreaking contributions to theoretical physics, including the theory of relativity and the concept of photons. His work revolutionized our understanding of space, time, and energy.

Correct Answer: To understand the fundamental laws of nature

Explanation: The primary goal of physics education is to enable students to understand the fundamental laws of nature and the principles governing physical phenomena. This knowledge forms the basis for scientific inquiry, technological advancements, and a deeper understanding of the universe.

Correct Answer: All of the above

Explanation: Ancient civilizations such as the Greeks, Chinese, Indians, and others made significant contributions to early physics. Greek philosophers like Aristotle and Archimedes laid foundations in mechanics and optics, while Indian and Chinese scholars made advancements in astronomy and materials science.

Correct Answer: To observe natural phenomena and validate theories

Explanation: Experimentation in physics involves systematically observing natural phenomena under controlled conditions to validate or refute theories and hypotheses. It provides empirical evidence that supports theoretical models and contributes to the development of scientific knowledge.

Correct Answer: Pure physics focuses on theoretical research, while applied physics focuses on practical applications.

Explanation: Pure physics seeks to understand fundamental principles and laws of nature through theoretical research, whereas applied physics applies these principles to solve practical problems and develop technologies for various industries.

Correct Answer: Isaac Newton

Explanation: Isaac Newton developed the laws of motion and universal gravitation in his work “Philosophiæ Naturalis Principia Mathematica” published in 1687. These laws laid the foundation for classical mechanics and explained the motion of objects on Earth and in space.

Correct Answer: It provides a systematic approach to prove hypotheses.

Explanation: The scientific method is crucial in physics as it provides a systematic approach to formulate hypotheses, conduct experiments, gather empirical data, and draw conclusions based on evidence. It ensures that scientific investigations are rigorous, reproducible, and objective.

Correct Answer: Speed

Explanation: Speed is a physical quantity that can be measured and quantified. It is defined as the rate of change of distance with respect to time and is expressed in units such as meters per second (m/s). Physical quantities are measurable attributes of objects or phenomena in the physical world.

Correct Answer: Johannes Kepler

Explanation: Johannes Kepler formulated the laws of planetary motion based on empirical observations made by Tycho Brahe. Kepler’s laws describe the orbits and motion of planets around the Sun, laying the groundwork for understanding celestial mechanics.

Correct Answer: Aristotle

Explanation: Aristotle proposed a geocentric model of the universe in which the Earth was considered the center, with celestial bodies moving in circular orbits around it. This model dominated Western thought for centuries until it was challenged by heliocentric models.

Correct Answer: Galileo Galilei

Explanation: Galileo Galilei is credited with inventing the telescope and making groundbreaking astronomical observations, including the moons of Jupiter and the phases of Venus. His work provided strong evidence for the heliocentric model of the solar system.

Correct Answer: Isaac Newton

Explanation: Isaac Newton formulated the laws of motion and universal gravitation in his work “Philosophiæ Naturalis Principia Mathematica” published in 1687. These laws revolutionized physics by explaining the motion of objects on Earth and in space.

Correct Answer: Michael Faraday

Explanation: Michael Faraday proposed the theory of electromagnetism and developed the laws of electromagnetic induction in the 19th century. His experiments demonstrated the relationship between electricity and magnetism, paving the way for modern electrical technology.

Correct Answer: Albert Einstein

Explanation: Albert Einstein proposed the theory of relativity, including the special and general theories, which revolutionized physics by redefining our understanding of space, time, and gravity. His work laid the foundation for modern cosmology and astrophysics.

Correct Answer: Chinese

Explanation: The Chinese civilization made significant contributions to early optics and astronomy, including the invention of the camera obscura and accurate astronomical observations. Chinese astronomers developed sophisticated calendars and studied celestial phenomena.

Correct Answer: Galileo Galilei

Explanation: Galileo Galilei is considered the father of modern experimental science for his systematic approach to experimentation and empirical observation. His work laid the foundation for the scientific method and the practice of experimental physics.

Correct Answer: Isaac Newton

Explanation: Isaac Newton proposed the laws of motion, including the concept of inertia, which states that an object at rest will remain at rest and an object in motion will remain in motion unless acted upon by an external force. These laws are fundamental to classical mechanics.

Correct Answer: Niels Bohr

Explanation: Niels Bohr contributed significantly to the understanding of quantum mechanics and wave-particle duality with his model of the atom and the principles of complementarity. His work laid the foundation for modern atomic and nuclear physics.

Correct Answer: Alhazen

Explanation: Alhazen, also known as Ibn al-Haytham, formulated the laws of optics, including the laws of reflection and refraction, during the Islamic Golden Age. His work laid the foundation for modern optics and experimental physics.

Correct Answer: Nicolaus Copernicus

Explanation: Nicolaus Copernicus proposed the heliocentric model of the solar system, challenging the prevailing geocentric model. He placed the Sun at the center, with the planets orbiting it, marking a significant shift in our understanding of the universe.

Correct Answer: Democritus

Explanation: Democritus, an ancient Greek philosopher, first proposed the concept of atomism, suggesting that all matter is composed of indivisible particles called atoms. His ideas laid the groundwork for modern atomic theory in physics and chemistry.

Correct Answer: Isaac Newton

Explanation: Isaac Newton developed the laws of motion in his work “Philosophiæ Naturalis Principia Mathematica,” published in 1687. These laws describe the relationship between the motion of an object and the forces acting on it, foundational to classical mechanics.

Correct Answer: Robert Millikan

Explanation: Robert Millikan conducted the oil drop experiment in 1909 to determine the fundamental charge of an electron. His work provided a precise measurement of the electron’s charge and contributed to our understanding of atomic structure.

Correct Answer: James Clerk Maxwell

Explanation: James Clerk Maxwell proposed the theory of electromagnetism and developed Maxwell’s equations in the 19th century. His equations unified electricity and magnetism into a single theory, predicting the existence of electromagnetic waves.

Correct Answer: Wilhelm Röntgen

Explanation: Wilhelm Röntgen discovered X-rays in 1895 while studying cathode rays, leading to their use in medical imaging and scientific research. His discovery revolutionized medicine and contributed to the development of modern physics.

Correct Answer: Albert Einstein

Explanation: Albert Einstein proposed the theory of special relativity in 1905, which revolutionized our understanding of space, time, and motion. The theory introduced concepts such as time dilation and length contraction, challenging classical mechanics.

Correct Answer: Max Planck

Explanation: Max Planck developed the laws of quantum mechanics, starting with his formulation of the quantum theory of radiation in 1900. His work introduced the concept of quantized energy levels and laid the foundation for modern physics.

Correct Answer: Werner Heisenberg

Explanation: Werner Heisenberg proposed the uncertainty principle as part of his contributions to quantum mechanics in the 1920s. The principle asserts that the more precisely the position of a particle is known, the less precisely its momentum can be known, and vice versa.

Correct Answer: Mechanics

Explanation: Mechanics is the branch of physics that deals with the study of motion and forces in bodies. It encompasses both kinematics, which describes motion without considering its causes, and dynamics, which focuses on the forces causing motion.

Correct Answer: Isaac Newton

Explanation: Isaac Newton formulated the three laws of motion in his work “Philosophiæ Naturalis Principia Mathematica,” published in 1687. These laws are foundational to classical mechanics and describe the behavior of objects under the influence of forces.

Correct Answer: Newton’s First Law

Explanation: Newton’s First Law of Motion states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. It is also known as the law of inertia.

Correct Answer: Newton’s Second Law

Explanation: Newton’s Second Law of Motion states that the force acting on an object is equal to the rate of change of its momentum, and occurs in the direction of the applied force. Mathematically, it is expressed as F = ma, where F is force, m is mass, and a is acceleration.

Correct Answer: Newton’s Third Law

Explanation: Newton’s Third Law of Motion states that for every action, there is an equal and opposite reaction. This law explains the interaction between two objects and the forces they exert on each other, ensuring conservation of momentum.

Correct Answer: Kinematics

Explanation: Kinematics is the branch of mechanics that deals with the motion of objects without considering the forces causing the motion. It focuses on describing motion in terms of displacement, velocity, acceleration, and time.

Correct Answer: Dynamics

Explanation: Dynamics is the branch of mechanics that deals with the forces causing the motion of objects. It investigates how forces interact with objects to produce motion, including the effects of mass, acceleration, and the laws of motion.

Correct Answer: Newton

Explanation: The SI unit of force is the Newton (N), defined by Newton’s Second Law of Motion. One Newton is the force required to accelerate a one-kilogram mass by one meter per second squared (1 N = 1 kg⋅m/s²).

Correct Answer: Isaac Newton

Explanation: Isaac Newton developed the principles of classical mechanics, which include the three laws of motion and the law of universal gravitation. His work laid the foundation for understanding motion, forces, and gravitation.

Correct Answer: Fluid Mechanics

Explanation: Fluid Mechanics is the branch of physics that studies the behavior of gases and liquids in motion, including their properties and the forces acting on them. It is crucial in understanding fluid dynamics, aerodynamics, and hydrodynamics.

Correct Answer: Newton’s Second Law

Explanation: Newton’s Second Law of Motion can be used to explain the behavior of an object sliding down an inclined plane by calculating the forces acting on the object and determining its acceleration along the incline.

Correct Answer: Law of Conservation of Energy

Explanation: The Law of Conservation of Energy states that the total energy of an isolated system remains constant over time, even if energy within the system changes form. This principle is fundamental in classical mechanics and thermodynamics.

Correct Answer: Celestial Mechanics

Explanation: Celestial Mechanics is the branch of mechanics that deals with the study of the motion of celestial objects such as planets, stars, and galaxies under the influence of gravitational forces. It applies principles of classical mechanics to astronomical phenomena.

Correct Answer: Johannes Kepler

Explanation: Johannes Kepler developed the laws of planetary motion, known as Kepler’s laws, in the early 17th century. His laws describe the elliptical orbits of planets around the Sun and laid the groundwork for Newton’s law of universal gravitation.

Correct Answer: Fermat’s Principle

Explanation: Fermat’s Principle states that the path taken between two points by a ray of light is the path that can be traversed in the least time. It is fundamental in optics and helps explain the behavior of light reflection and refraction.

Correct Answer: Isaac Newton

Explanation: Isaac Newton developed the laws of motion, which include the concept of inertia (First Law) and the principle of action and reaction (Third Law). His laws are essential in understanding classical mechanics and dynamics.

Correct Answer: Statics

Explanation: Statics is the branch of physics that deals with the study of the equilibrium of systems under the action of forces and moments (torques). It examines how forces balance each other in stationary objects or systems.

Correct Answer: Newton’s First Law

Explanation: Newton’s First Law of Motion explains why astronauts experience weightlessness in space. In the absence of external forces, objects (including astronauts) in motion will remain in motion with constant velocity or at rest if initially at rest.

Correct Answer: Aerodynamics

Explanation: Aerodynamics is the branch of mechanics that deals with the study of the motion of projectiles (such as aircraft) and the effects of air resistance on their motion. It is crucial in designing efficient aircraft and understanding fluid dynamics in air.

Correct Answer: Archimedes’ Principle

Explanation: Archimedes’ Principle states that the force exerted by a fluid on an immersed object (buoyant force) is upward and equal to the weight of the fluid displaced by the object. It explains why objects float or sink in a fluid medium.

Correct Answer: Quantum Mechanics

Explanation: Quantum Mechanics is the branch of physics that deals with the study of the behavior of matter and energy at the atomic and subatomic levels. It describes phenomena such as quantization of energy levels, wave-particle duality, and uncertainty principles.

Correct Answer: Louis de Broglie

Explanation: Louis de Broglie proposed the wave-particle duality concept, suggesting that particles exhibit both wave-like and particle-like behavior. This idea laid the foundation for understanding quantum mechanics and the behavior of matter on microscopic scales.

Correct Answer: Heisenberg Uncertainty Principle

Explanation: The Heisenberg Uncertainty Principle states that it is impossible to simultaneously determine the exact position and momentum of a particle with arbitrary precision. This principle has profound implications for quantum mechanics and measurement processes.

Correct Answer: Schrödinger Equation

Explanation: The Schrödinger Equation describes how the quantum state of a physical system changes with time. It is a fundamental equation in quantum mechanics, used to calculate wave functions and predict the behavior of particles at microscopic scales.

Correct Answer: Emission Spectra

Explanation: Emission Spectra explain the emission of light by atoms when electrons jump between energy levels. These spectral lines are unique to each element and provide valuable information about atomic structure and energy transitions.

Correct Answer: Max Planck

Explanation: Max Planck introduced the concept of quantized energy levels in his explanation of blackbody radiation, laying the foundation for quantum theory. Planck’s discovery led to the development of quantum mechanics as a distinct branch of physics.

Correct Answer: Wave-particle duality

Explanation: Wave-particle duality describes the tendency of particles to exhibit wave-like behavior, especially evident in experiments like the double-slit experiment. This concept is central to understanding quantum mechanics and the nature of matter.

Correct Answer: Quantum Entanglement

Explanation: Quantum Entanglement states that two or more particles can become entangled, such that their quantum states are interdependent regardless of the distance between them. This phenomenon has implications for quantum computing and communication.

Correct Answer: Quantum Theory of Matter

Explanation: Quantum Theory of Matter deals specifically with the behavior of particles at the atomic scale, involving probabilistic predictions and describing phenomena such as electron behavior in atoms and solids.

Correct Answer: Niels Bohr

Explanation: Niels Bohr proposed the quantization condition for angular momentum in atoms, leading to the Bohr model of the atom. His model successfully explained atomic spectra and contributed to the development of quantum mechanics.

Correct Answer: Energy Quantization

Explanation: Energy Quantization in quantum mechanics explains that particles such as electrons can occupy only discrete energy levels within an atom. This concept is fundamental to understanding atomic spectra and electron behavior.

Correct Answer: Planck’s Equation

Explanation: Planck’s Equation describes the relationship between the energy (E) and frequency (ν) of a photon: E = hν, where h is Planck’s constant. This equation is crucial in quantum mechanics and the study of electromagnetic radiation.

Correct Answer: Quantum Tunneling

Explanation: Quantum Tunneling is the phenomenon in quantum mechanics that allows particles to pass through potential barriers that would be classically impossible to cross. It is essential in understanding atomic nuclei stability, scanning tunneling microscopy, and semiconductor devices.

Correct Answer: Pauli Exclusion Principle

Explanation: The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of quantum numbers (specifically, the same quantum state). This principle is fundamental in understanding atomic structure and chemical bonding.

Correct Answer: Albert Einstein

Explanation: Albert Einstein developed the quantum theory of electromagnetic radiation, which explained the photoelectric effect by proposing that light consists of particles (photons) with discrete energies. This theory contributed significantly to quantum mechanics.

Correct Answer: De Broglie Hypothesis

Explanation: The De Broglie Hypothesis in quantum mechanics describes the wave-like nature of particles, suggesting that every particle exhibits wave-like properties with a wavelength inversely proportional to its momentum.

Correct Answer: Schrödinger Equation

Explanation: The Schrödinger Equation in quantum mechanics describes the wave function of a particle and its evolution over time. The probability distribution of finding a particle in a particular state is given by the square of the wave function.

Correct Answer: Correspondence Principle

Explanation: Bohr’s Correspondence Principle in quantum mechanics states that the classical description of macroscopic systems must emerge from the quantum description of microscopic systems as the scale of observation increases.

Correct Answer: Quantum Statistical Mechanics

Explanation: Quantum Statistical Mechanics deals with the statistical behavior of large ensembles of particles, considering quantum effects such as indistinguishability and quantum states’ occupation probabilities.

Correct Answer: Quantum Entanglement

Explanation: Quantum Entanglement explains the instantaneous influence of one particle’s quantum state on another, even when separated by large distances. This phenomenon has implications for quantum information and communication.

Correct Answer: Thermodynamics

Explanation: Thermodynamics is the branch of physics that deals with the study of heat, temperature, and their relation to energy and work. It includes principles such as the laws of thermodynamics and their applications in various systems.

Correct Answer: Optics

Explanation: Optics is the branch of physics that deals with the behavior and properties of light, including its interactions with matter (reflection, refraction, dispersion) and its propagation through space. It encompasses topics like lenses, mirrors, and optical instruments.

Correct Answer: Electromagnetism

Explanation: Electromagnetism is the branch of physics that deals with the study of electric charges, electric and magnetic fields, and their interactions with magnets and currents. It includes Maxwell’s equations and the principles governing electromagnetic waves.

Correct Answer: Nuclear Physics

Explanation: Nuclear Physics is the branch of physics that deals with the study of the structure, properties, and behavior of atomic nuclei and the particles that compose them. It includes topics like nuclear reactions, radioactive decay, and nuclear energy.

Correct Answer: Particle Physics

Explanation: Particle Physics is the branch of physics that deals with the study of the fundamental forces and particles that make up the universe. It includes the development and testing of theories like the Standard Model, which describes elementary particles and their interactions.

Correct Answer: Solid State Physics

Explanation: Solid State Physics is the branch of physics that deals with the study of the behavior and properties of materials in their solid phase. It includes topics like crystal structures, semiconductors, magnetic materials, and superconductors.

Correct Answer: Fluid Dynamics

Explanation: Fluid Dynamics is the branch of physics that deals with the study of the motion and properties of fluids (liquids, gases, and plasmas). It includes topics like fluid flow, turbulence, boundary layers, and aerodynamics.

Correct Answer: Astrophysics

Explanation: Astrophysics is the branch of physics that deals with the study of the universe, including its origins, evolution, and phenomena such as galaxies, stars, planets, and cosmic radiation. It combines principles from astronomy and physics to understand celestial objects and phenomena.

Correct Answer: Thermodynamics

Explanation: Thermodynamics is the branch of physics that deals with the study of heat, temperature, energy, and their transformations. It includes principles such as the laws of thermodynamics and their applications in various systems.

Correct Answer: Solid State Physics

Explanation: Solid State Physics is the branch of physics that deals with the study of the properties and behavior of matter in bulk quantities, such as solids and liquids. It encompasses topics like crystal structures, phase transitions, and material properties.