Physics paper 2

Study Notes

Specific heat capacity is the amount of heat energy required to raise the temperature of 1 kg of a substance by 1°C.
It is measured in joules per kilogram per degree Celsius (J/kg°C).
Different substances have different specific heat capacities.
Water has a relatively high specific heat capacity of approximately 4200 J/kg°C.
High specific heat capacity means a substance can absorb or release a large amount of heat with only a small change in temperature.
Importance: influences thermal properties of materials, essential in applications like cooking, heating systems, and engineering design for energy efficiency.

A transformer consists of two coils of wire (primary and secondary) wound around a common magnetic core.
Operation is based on the principle of electromagnetic induction.
Alternating current in the primary coil creates a changing magnetic field in the core, inducing voltage in the secondary coil.
Types of transformers:
- Step-up transformers increase voltage (fewer turns on primary coil, more on secondary coil).
- Step-down transformers decrease voltage (more turns on primary coil, fewer on secondary coil).
Importance: crucial in electrical power distribution, step-up voltage for long-distance transmission, and step-down voltage for safe household use.

Red shift refers to the phenomenon where light from distant galaxies or celestial objects appears redder than expected due to the universe's expansion.
The Doppler effect causes the wavelength of light to stretch, resulting in the red shift.
Evidence of expansion: discovery of the red shift in galaxy spectra by Edwin Hubble.
Big Bang Theory proposes that the universe began around 13.8 billion years ago from an extremely hot and dense state and has been expanding ever since.
Cosmic microwave background radiation detected in all directions of the sky is considered residual heat from the Big Bang.
Implications: revolutionized our understanding of cosmology, explaining the origin and evolution of the universe, and shaping our modern view of astronomy and physics.

When electric current flows through a straight wire, it generates a magnetic field around the wire.
Direction of magnetic field lines can be determined using the right-hand grip rule (thumb points in the direction of the current, fingers curl in the direction of the magnetic field).
A coil or solenoid is a series of loops of wire wound in a cylindrical shape, creating a more concentrated and stronger magnetic field inside the coil.
Importance: used in electromagnets and devices where controlled magnetic fields are necessary.