“Prepare for physics excellence with our specialized ‘Class 9 Physics Notes.’
Customized for the new curriculum, these notes comprehensively address essential concepts and exam patterns, establishing themselves as your primary resource for thorough preparation. Within, discover succinct responses to paper questions, accompanied by diagrams enhancing your comprehension.”
Short Answer Questions.
(a) Electricity and Magnetism.
Answer. Electricity and Magnetism: Electricity deals with the study of electric charges and their movement, while magnetism involves the behavior of magnets and magnetic fields. Together, they form the basis of electromagnetism, a fundamental force governing the interaction between charged particles and magnetic objects.
(b) Least Count of Vernier Calipers.
Answer. Least Count of Vernier Calipers: The least count of Vernier calipers is the smallest measurement that can be read directly from the instrument. It is determined by the division of the smallest main scale division by the number of divisions on the Vernier scale.
(c) Displacement.
Answer. Displacement: Displacement is a vector quantity representing the change in position of an object. It is the straight-line distance and direction from the initial to the final position.
(d) Acceleration.
Answer. Acceleration: Acceleration is the rate of change of velocity with respect to time. It can be calculated by dividing the change in velocity by the time interval.
(e) Limiting Friction.
Answer. Limiting Friction: Limiting friction is the maximum frictional force that opposes the relative motion or tendency of motion between two surfaces in contact. It occurs just before the object starts moving.
(f) Two Disadvantages of Friction.
Answer. Two Disadvantages of Friction: Friction causes wear and tear of materials and can result in the loss of energy in mechanical systems.
(g) First Condition of Equilibrium.
Answer. First Condition of Equilibrium: The first condition of equilibrium states that the vector sum of all the external forces acting on an object must be zero for the object to be in static equilibrium.
(h) Energy.
Answer. Energy: Energy is the capacity to do work. It exists in various forms such as kinetic, potential, thermal, and chemical energy.
(i) Elasticity.
Answer. Elasticity: Elasticity is the property of a material to return to its original shape and size after the removal of a deforming force. It is characterized by Hooke’s Law.
(j) Young Modulus.
Answer. Young’s Modulus: Young’s Modulus is a measure of a material’s stiffness and is the ratio of stress to strain within the elastic limit.
(k) Negative Acceleration.
Answer. Negative Acceleration: Negative acceleration, also known as deceleration, occurs when an object is slowing down. It is represented by a negative value in calculations.
(l) Derived Quantities.
Answer. Derived Quantities: Derived quantities are physical quantities derived from the combination of base quantities. Examples include velocity, acceleration, and force.
(m) Work’s Unit.
Answer. Work’s Unit: The unit of work is the joule (J) in the International System of Units (SI).
(n) Centre Of Mass.
Answer. Centre of Mass: The center of mass is the point in an object or system where its mass can be considered to be concentrated. It is the balance point for an object under the influence of gravity.
(o) Strain.
Answer. Strain: Strain is the measure of the deformation or change in shape of a material relative to its original shape. It is often expressed as a ratio of the change in dimension to the original dimension.
