Physics Section 13

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• Area under velocity-time graph represents displacement.
• Instantaneous and average velocities become equal when the body has uniform acceleration.
• Inertia of an object is a quantitative measure of its mass.
• The 1st law of motion gives the definition of rest.
• The 3rd law of motion explains the existence of a pair of forces in nature.
• The dimension of force is MLT-2.
• The pair that has the same direction always is force, acceleration.
• The collision between two bodies can be elastic if bodies are elastic.
• When a car takes a turn around a curve road, the passengers feel a force due to their inertia.
• The shape of the velocity-time graph for constant acceleration is a straight inclined line.
• The correct relation between time of flight T and maximum height H is H = gT²/8.
• Taking off a rocket can be explained by the 3rd law of motion.
• The angle of projection for which the range and maximum height become equal is tan⁻¹2.
• Distance covered by a freely falling body in 2 seconds will be 19.6 m.
• Flight of a rocket in space is an example of the 3rd law of motion.
• The angle at which the range of the projectile is maximum is 45 degrees.
• Time rate of change of momentum is equal to impulse.
• Ballistic missiles fail due to their shape, air resistance, and angle of projection.
• When a body is moving with uniform velocity, its acceleration changes.
• When the velocity-time graph is a straight line parallel to the time axis, acceleration is zero.
• The slope of the velocity-time graph is acceleration.
• The law of motion that is also called the law of inertia is the 1st law.
• Newton’s laws do not hold good for particles that move with velocity comparable to the velocity of light.
• The 2nd law of motion gives the definition of force.
• Momentum depends upon both the mass and velocity of the body.
• When a body moves in a straight line, its displacement coincides with distance.
• A motorcycle safety helmet extends the time of collision, decreasing the force acting.
• During a long jump, an athlete runs before taking the jump to increase his momentum.
• A body falling freely under gravity falls a distance of 20 m during an interval between 1st and 2nd seconds.
• The SI unit of heat is Joule.
• Two automobiles will meet in 1.5 hours.
• The branch of science dealing with the properties of matter and energy is Physics.
• Physics is one of the branches of Physical science.
• Physics plays an important role in engineering.
• Physics provides basic principles and fundamental laws to other branches of science.
• The branch of Physics dealing with highly energetic ions is Plasma physics.
• The branch of Physics dealing with nuclear particles such as neutrons, protons, and nuclear structure is Nuclear Physics.
• The branch of physics dealing with the properties of gravitational fields is Field theory.
• The branch of physics that deals with living things is Biological sciences.
• The physics of moving charged particles is known as Electro-dynamics.
• The study of living science relates to Biological science.
• The first book of Physics was written by Aristotle.
• The particle that is massless is Photon.
• The branch of science dealing with the study of sound and sound waves is Acoustics.
• The formula for the inter-conversion of centigrade and Fahrenheit scale is f – 32/9 = c/5.
• The coefficient of linear expansion is equal to ΔL/LΔT.
• The unit of the coefficient of linear expansion or volume expansion is K-1.
• Linear expansion occurs in solid and liquid.
• When a body is in motion, its momentum always changes.
• A man in a car moving with a velocity of 36 km/hr has a speed with respect to the car of 0 m/s.
• When two bodies move toward each other with constant speeds, their speeds are 3 m/s, 3 m/s.
• The distance covered by a body in time t starting from rest is at²/2.
• The trajectory (or path) of a projectile is a parabola.
• The force exerted by a wall on which water strikes normally at a speed of 10 m/s and at a discharge of 0.0001 m³/s is 10 N.
• The range of the projectile at 30 degrees and 60 degrees are equal to each other.
• Waves transmit energy from one place to another.
• When collision between the bodies in a system is inelastic in nature, the momentum changes but kinetic energy remains conserved.
• The acceleration in the rocket at any instant is proportional to the nth power of the velocity of the expelled gases, where n must be -2.
• The kinetic energy of an object is directly proportional to its mass and the square of its velocity.
• The condition for equilibrium of a body is that the net force and net torque acting on it are both zero.
• The object with the highest frequency in the electromagnetic spectrum is Gamma rays.
• The phenomenon of splitting of light into its seven constituent colors is Dispersion.
• The phenomenon that explains why the sky is blue is Rayleigh scattering.
• A lens that converges parallel rays of light is Convex lens.
• The type of mirror used in a rear-view mirror in a car is Convex mirror.
• The wavelength of visible light ranges from approximately 400 to 700 nanometers.
• The process of heat transfer that doesn’t require a medium is Radiation.
• The device used to measure atmospheric pressure is a Barometer.
• The process that converts a solid directly into a gas is Sublimation.
• The process of converting a gas into a liquid is Condensation.
• The property of a material that allows it to be drawn into a wire is Ductility.
• The process of separating components in a solution based on their boiling points is Distillation.
• The process of converting a liquid into a gas at temperatures below its boiling point is Evaporation.
• The process of changing a liquid into a solid by cooling is Freezing.
• The process of converting a liquid into a gas at its boiling point throughout the liquid is Boiling.
• The atomic number of an element is determined by the number of protons in its nucleus.
• An element with the same number of protons but a different number of neutrons is called an Isotope.
• The most abundant gas in the Earth’s atmosphere is Nitrogen.
• The process by which plants convert light energy into chemical energy is Photosynthesis.
• The substance that speeds up a chemical reaction without being consumed in the reaction is Catalyst.
• The type of reaction where two or more substances combine to form a single product is Synthesis.
• The pH value of a neutral solution is 7.
• The force that opposes the motion of an object through a fluid is Drag force.
• The type of electromagnetic radiation used for communication in optical fibers is Infrared.
• The phenomenon responsible for the “Red Shift” in the spectra of galaxies is the Doppler effect.
• The process of a solid directly changing into a gas without passing through the liquid phase is Sublimation.
• The process of a gas changing directly into a solid without passing through the liquid phase is Deposition.
• The particle that carries a positive charge in an atomic nucleus is a Proton.
• The particle that carries no charge in an atomic nucleus is a Neutron.
• The process of energy production in the Sun through nuclear fusion is Fusion.
• The force that keeps planets in orbit around the Sun is Gravity.
• The process of a nucleus spontaneously decaying and emitting radiation is Radioactive decay.
• The bending of light as it passes from one medium to another is Refraction.
• The bending of a wave around an obstacle is Diffraction.
• The bending of light around an edge or slit is Interference.
• The unit of electric current is Ampere.
• The process of splitting an atomic nucleus into smaller fragments is Nuclear fission.
• The process of using controlled nuclear reactions to release energy is Nuclear power.
• The process of converting alternating current (AC) to direct current (DC) is Rectification.
• The force experienced by a current-carrying conductor in a magnetic field is Magnetic force.