Std. 11
Physics

A measurable property expressed by a numerical value and a unit.

Standard units allow measurements to be compared and communicated clearly.

They indicate the meaningful digits in a measured value and reflect measurement precision.

[Q] = MᵃLᵇTᶜ
Dimensions help check equations and convert units.

A scalar has magnitude only, such as mass, time and temperature.

A vector has magnitude and direction, such as displacement, velocity and force.

Vectors are combined according to their directions to obtain a resultant vector.

v = dx/dt    a = dv/dt
Velocity is the rate of change of position and acceleration is the rate of change of velocity.

x = ∫v dt    v = ∫a dt
Integration helps recover a quantity when its rate of change is known.

Motion involving two perpendicular directions. Projectile and circular motion are important examples.

A projectile has horizontal motion while gravity produces vertical acceleration when air resistance is neglected.

T = 2u sinθ / g

H = u²sin²θ / 2g

R = u²sin2θ / g

An object remains at rest or in uniform straight-line motion unless acted upon by a net external force. This introduces inertia.

Inertia is the tendency of an object to resist a change in its state of motion.

F = ma
For constant mass, net force produces acceleration in the direction of the force.

Interactions produce equal and opposite forces acting on different bodies.

p = mv    J = Δp

Every mass attracts every other mass. This universal attraction governs falling objects and orbital motion.

F = Gm₁m₂ / r²

It is the acceleration produced by Earth's gravitational field near its surface.

They describe planetary motion and connect observation with gravitational theory.

vₑ = √(2GM/R)

The property by which a material tends to regain its original shape after the deforming force is removed, within its elastic limit.

Internal restoring force developed per unit area when a material is deformed.

Relative deformation produced in a material; it has no unit.

Y = longitudinal stress / longitudinal strain

The greatest deformation for which the material can return to its original form.

Most substances change dimensions when their temperature changes.

Q = mcΔT

It uses conservation of energy to analyse heat exchange between bodies.

Q = mL
Energy transferred during a change of state without a corresponding temperature change.

Heat can be transferred by conduction, convection and radiation.

Sound is a mechanical wave produced by vibrating sources and requires a material medium.

Frequency is the number of oscillations per second and is measured in hertz.

Wavelength is the distance between successive points in the same phase.

v = fλ

Large amplitude response occurs when a system is driven at or near its natural frequency.

Reflection is the return of light into the original medium after striking a surface.

Refraction is the change in direction of light when it enters another transparent medium because its speed changes.

It occurs when light travels from a denser to a rarer medium and the incidence angle exceeds the critical angle.

P = 1/f
With f in metres, power is expressed in dioptres.

Microscopes and telescopes use lenses or mirrors to form useful magnified images.

A fundamental property responsible for electric interactions. Positive and negative charges exist and total charge is conserved.

F = (1/4πε₀)|q₁q₂|/r²

Electric field at a point describes force per unit positive test charge.

It is potential energy per unit positive charge relative to a chosen reference.

A pair of equal and opposite charges separated by a small distance forms an electric dipole.

I = Q/t
Current is the rate of flow of electric charge.

V = IR

Resistance measures opposition to current and depends on material, dimensions and temperature.

R = ρL/A

P = VI = I²R = V²/R

The region where a magnet, magnetic pole or moving charge experiences magnetic effects.

Electric current produces a magnetic field around a conductor.

A current-carrying conductor can experience force in a magnetic field.

A current loop in a magnetic field can experience a turning effect, the principle behind electric motors.

A current-carrying coil can act as a magnet and its strength can be controlled.

It consists of oscillating electric and magnetic fields and can travel through vacuum.

Mechanical waves require a material medium; electromagnetic waves do not.

Radio, microwave, infrared, visible, ultraviolet, X-ray and gamma radiation form the spectrum.

Modulation changes a property of a carrier wave according to an information signal.

A source, transmitter, channel and receiver work together to transfer information.

A material whose conductivity lies between that of a good conductor and an insulator and can be controlled by conditions and impurities.

Controlled addition of suitable impurities to alter semiconductor conductivity.

In p-type material holes are majority carriers; in n-type material electrons are majority carriers.

Joining p-type and n-type regions creates a junction with a depletion region and potential barrier.

A semiconductor device that conducts much more readily in one direction than the other.