Current Electricity — Class 12 Maharashtra HSC Physics revision notes
A 6-page visual revision sheet for Current Electricity, written for Class 12 Maharashtra HSC Physics. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
What this Current Electricity sheet covers
- junction
- loop
- branch
- Junction, loop, branch
- kirchhoff's first law
- junction law
- Kirchhoff's first law: current law (junction law)
- algebraic sum of currents at a junction is zero
- sign convention
- kirchhoff's second law
- loop law
- voltage law
- Kirchhoff's second law: voltage law (loop law)
- sum of IR drops and emfs around any closed loop is zero
- Steps for solving a network
- wheatstone bridge
- The Wheatstone bridge
- balanced wheatstone bridge
- balance condition
- loop ABDA with I_g=0
- loop BCDB with I_g=0
- dividing the two, the balance condition
- Applications of the bridge
- metre bridge
- The metre bridge
- metre bridge balance
- unknown resistance metre bridge
- balance condition, l_x and l_R the two wire lengths
- unknown resistance
- specific resistance of the unknown wire X, radius r, length L
- post office box
- The post office box
- Metre bridge vs post office box
- potentiometer
- Potentiometer, the principle
- comparing emf
- sum and difference method
- Comparing the emf of two cells
- null lengths l_1 and l_2 correspond to emf epsilon_1 and epsilon_2
- so the emfs compare directly as lengths
- sum and difference method, componendo-dividendo
- internal resistance
- internal resistance of a cell
- open circuit, null length l_1 corresponds to emf epsilon
- closed through a known resistance R, null length l_2 corresponds to terminal voltage V
- voltage divider
- Potentiometer as a voltage divider
- galvanometer to ammeter
- shunt resistance
- Galvanometer to ammeter: the shunt
- shunt S in parallel carries the rest of the current, GI_g=S(I-I_g)
- to extend the range n times, I=nI_g
- fraction of the total current through the shunt
- galvanometer to voltmeter
- series resistance voltmeter
- Galvanometer to voltmeter: the series resistor
- resistance X in series drops the remaining voltage, V=I_g(G+X)
- to extend the range n_V times
- Symbols
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Physics chapter by chapter against your real exam dates and free hours, and when the plan reaches Current Electricity the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.
More Physics Class 12 revision notes
- AC Circuits
- Dual Nature of Radiation and Matter
- Electromagnetic Induction
- Electrostatics
- Kinetic Theory of Gases and Radiation
- Magnetic Fields due to Electric Current
- Magnetic Materials
- Mechanical Properties of Fluids
- Oscillations
- Rotational Dynamics
- Semiconductor Devices
- Structure of Atoms and Nuclei
- Superposition of Waves
- Thermodynamics
- Wave Optics