KCET Current Electricity Topics 2025

KCET Current Electricity Topics Topics 2025: KCET Current Electricity Topics constitute an important section of the KCET Second-Year PUC Physics Syllabus.KCET 2025Current Electricity Topics include Introduction to Electric Current, Ohm’s Law, Resistivity of Various Materials, Electrical Energy and Power, Cells, Emf, Internal Resistance, Kirchhoff’s Rules, Wheatstone Bridge, Numericals Etc. Candidates seeking admission through the KCET 2025 exam need to be familiar with the list of important topics under the KCET Current Electricity section. Preparing such topics in an efficient manner is an excellent approach which will help the candidates gain an advantage in the KCET 2025 exam . We have noted down all the key topics of KCET Current Electricity from the KCET 2025 syllabus. Candidates are advised to read the article thoroughly for detailed information related to the KCET Current Electricity Topics 2025.

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KCET Current Electricity Topics 2025

The topics covered under the KCET Current Electricity section have been discussed below.

KCET Physics Current Electricity Topics (2nd PUC)

Current:

Current via a given area of a conductor is the net charge passing per unit time through the area.

Emf:

Emf refers to electromotive force which is the voltage difference between the two terminals of a source in an open circuit.

Ohm’s law:

The electric current I flowing through a substance is proportional to the voltage V across its ends, i.e., or V = RI.

where R is referred to the resistance of the substance.

The unit of resistance is ohm.

Resistance (R):

Resistance (R) of a conductor depends upon its length “l” and constant cross-sectional area “A” through the relation,

Where ρ, called resistivity, is a property of the material and depends on temperature and pressure.

Electrical resistivity:

The electrical resistivity of substances varies over a very wide range.

• Metals have low resistivity, in the range of 10–8 Ω m to 10–6 Ω m.
  Insulators such as glass and rubber have 1022 to 1024 time’s greater resistivity.
  Semiconductors such as Si and Ge lie roughly in the middle range of resistivity on a logarithmic scale.

Current density:

Current density (j) gives the amount of charge flowing per second per unit area normal to the flow , where n is the number density (number per unit volume) of charge carriers each of charge q.

is the drift velocity of the charge carriers.

For electrons q = –e ,

if j is normal to a cross-sectional area A and is constant over the area, the magnitude of the current I through the area is,

Using E = V/l, and Ohm’s law,

one obtains,

• The proportionality between the force eE on the electrons in a metal due to the external field E and the drift velocity Vd (not acceleration) can be understood, if one assumes that the electrons suffer collisions with ions in the metal, which deflect them randomly. If such collisions occur on an average at a time interval ,

where a is the acceleration of the electron.

This gives ,

In the temperature range in which resistivity increases linearly with temperature, the temperature coefficient of resistivity α is defined as the fractional increase in resistivity per unit increase in temperature.

Ohm’s law is obeyed by many substances, but it is not a fundamental law of nature.

It fails if:

(a) V depends on I non-linearly.

(b) The relation between V and I depends on the sign of V for the same absolute value of V.

(c) The relation between V and I is non-unique.

• An example of (a) is when ρ increases with I (even if temperature is kept fixed). A rectifier combines features (a) and (b). GaAs shows the feature (c).

When a source of emf ε is connected to an external resistance R, the voltage Vext  across R is given by,

where r is the internal resistance of the source.

(a) Total resistance R of n resistors connected in series is given by,

(b) Total resistance R of n resistors connected in parallel is provided by,

using which the value of one resistance can be determined, knowing the other three resistances.

The Potentiometer:

The potentiometer refers to a device to compare potential differences. Since the method involves a condition of no current flow, the device can be used to measure potential differences; and internal resistance of a cell and compare emf’s of two sources.

Best Books to Prepare for KCET Physics 2025

Candidates appearing for the KCET 2025 exam should be aware of the best books available in the market for their preparations. With the help of KCET Best Books 2025, candidates can check important topics and chapters asked in the KCET exam previously. The best books for KCET Physics preparation have been tabulated below.

• Physics for Karnataka CET and COMEDK
• NCERT books of Class 11 and 12 for Physics
• Physics for Karnataka CET and COMEDK by K. L. Gomber and K. L. Gogia
• Physics for 1st Year PUC by AS Govind
• Fundamentals of Physics by S Chand
• Pradeep’s Fundamental Physics (Class 11 and 12)

KCET Physics Exam Pattern 2025

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