Below is a concise list of key definitions from Chapter 7: Oscillations

Below is a concise list of key definitions from Chapter 7: Oscillations of the 11th Class Physics syllabus for the Federal Board of Intermediate and Secondary Education (FBISE), aligned with the National Book Foundation (NBF) curriculum. These definitions cover the essential concepts related to oscillations as typically presented in this chapter.

1. Oscillation: The repetitive back-and-forth motion of an object about a central position or equilibrium point.
2. Periodic Motion: Motion that repeats itself at regular intervals of time (e.g., oscillation of a pendulum).
3. Simple Harmonic Motion (SHM): A type of periodic motion where the restoring force is directly proportional to the displacement and acts opposite to it, described by F = -kx.
4. Amplitude (A): The maximum displacement of an oscillating object from its equilibrium position, measured in meters.
5. Time Period (T): The time taken to complete one full cycle of oscillation, measured in seconds.
6. Frequency (f): The number of oscillations completed per unit time, given by f = 1/T, measured in hertz (Hz).
7. Angular Frequency (ω): The rate of change of angular displacement in SHM, given by ω = 2πf = 2π/T, measured in radians per second (rad/s).
8. Restoring Force: The force that acts to bring an oscillating object back to its equilibrium position, proportional to displacement in SHM.
9. Spring Constant (k): A measure of the stiffness of a spring, defined as the force per unit extension, given by k = F/x, measured in newtons per meter (N/m).
10. Displacement (x): The distance of an oscillating object from its equilibrium position at any instant, measured in meters.
11. Phase: The stage of an oscillation cycle at a given time, described by the angle ωt + φ in the equation of SHM, x = A sin(ωt + φ).
12. Phase Constant (φ): The initial angle in the SHM equation that determines the starting point of the oscillation.
13. Simple Pendulum: A small mass (bob) suspended by a light, inextensible string that oscillates under gravity, approximating SHM for small angles.
14. Time Period of Simple Pendulum: The time for one complete oscillation, given by T = 2π√(L/g), where L is the length of the pendulum and g is gravitational acceleration.
15. Time Period of Mass-Spring System: The time for one complete oscillation, given by T = 2π√(m/k), where m is the mass and k is the spring constant.
16. Damped Oscillations: Oscillations where the amplitude decreases over time due to energy loss from resistive forces (e.g., friction, air resistance).
17. Damping: The process by which oscillatory motion is reduced due to energy dissipation, often caused by external forces like friction.
18. Natural Frequency: The frequency at which a system oscillates freely without external forces, determined by its physical properties (e.g., f = (1/2π)√(k/m) for a mass-spring system).
19. Forced Oscillations: Oscillations driven by an external periodic force, causing the system to oscillate at the driving frequency.
20. Resonance: The phenomenon where an oscillating system achieves maximum amplitude when the driving frequency matches its natural frequency.
21. Energy in SHM: The total mechanical energy in SHM, conserved in the absence of damping, given by E = ½ kA², alternating between kinetic and potential forms.
22. Potential Energy in SHM: The energy stored due to displacement in SHM, given by PE = ½ kx², where x is displacement.
23. Kinetic Energy in SHM: The energy due to the motion of the oscillating object, given by KE = ½ mv², where v.Concurrent forces is velocity.

These definitions cover the core concepts of oscillations from Chapter 7 of the FBISE 11th Class Physics curriculum. If you need further clarification or additional terms, feel free to ask!