 All 2 Mark Important Derivation - Physics Exam 2023 - Ezee Notes ## 1. What are quipotential surafes or Mention any two properties of Equipotential surafaces

1. Equipotnetial surfaces are those which have same potential at each and every single point.
2. The work done to move a charge from one point to another point is always zero.
3. Equipotential sufaces are always perpendicular to the Electric field lines.

## 2. What are the factors affecting resistance.

1. Area of the plates
2. Distance between the plates
3. Dielectric constant of the medium in between

## 3. What is electrostatic shielding

The process of protecting a certain region from external electric field by making a cavity in it is called as Electrostatic Shielding.

## 4. Define electric potential and write the expression

It is defined as the amount of work in carrying a unit positive charge from infinity to a particular point. ## 5. What is the expression for force on a chage in magnetic field , when is it maximum and when is it minimum?

F = qvBsinϴ

• It is maximum when sinϴ is maximum that is at 90 degrees.
• It is minimum when sinϴ is minimum that is at 0 degree.

## 6. Neat labelled diagram of cyclotron ## 7. Uses is cylotron

1. Used to accelerate charged particles or ions to a very high speed.
2. For radiation therapy in the treatment of cancer, different cyclotrons are used

## 8. Ampere circuital law

The line integral of the magnetic field surrounding closed-loop equals to the μo of times the algebraic sum of currents passing through the loop

## 9. Gauss law of magnetism

The net magnetic flux through any closed surface is always zero.

## 10. Curie Law

For a paramagnetic material the magnetic susceptibility is inversely proportional to the absolute temperature.

## 11. Properties of para , ferro and dia magnetic materials ## 12. Intensity of magnetising field , intensity of magnetisation , magnetic susceptibility Faradays First Law : It states that whenever there is magnetic flux linking with coil changing then there is a Emf induced in the coil, and it will last until the change.

Faraday’s Second Law : The magnitude of Emf induced in the coil is directly proportional to rate of change of flux linked with the coil.

## 14. Lenz correction

Lenz made a correction to faraday’s second law that the induced Emf is such that it tends to produce a current which opposes the change in magnetic flux that produced it.

## 15. Energy losses in tranformer.

1. Losses due to flux leakage
2. Eddy current losses
3. Heating of the materials

## 16. Uses of any one waves ( micro,uv,x,infra etc) ## 17. What is power factor, what is power factor for resistive circuit , what is power factor for inductive and capacitive circuit.

Power factor is given by cosϕ = R / Z

1. In a resistive circuit the power factor will be cosϕ = R/R = 1
2. In a capacitive or inductive circuit power factor will be cosϕ = 0

## 18. What is resonant frequency.

The current in a series LCR circuit is maximum when the inductive reactance and capacitive reactance are equal. This condition is called as Electric Resonance.

The frequency of AC at which resonance takes place is aclled as Resonant frequency (fo)

## 19. Define RMS , mean and peak value

Instantaneous Values : The value of voltage or current at a particular instant of time is called the instantaneous value.

Peak values : The maximum value of voltage or current over a particular cycle is called as peak value.

Average values : The mean of all the instantaneous values of voltage or current over half a cycle is called average value.

RMS [Root mean square] value : It is basically the root mean of squares of all the instantaneous values of voltage or current over a particular cycle.

## 20. State Brewster law

According to Brewster’s law, when unpolarized light is incident on a transparent substance surface, it experiences maximum plan polarization at the angle of incidence whose tangent is the refractive index of the substance for the wavelength.

## 21. Difference between Diffraction and interference ## 23. Malus law

It states that the intensity of plane-polarized light that passes through a analyzer varies directly with the square of the cosine of the angle between the plane of the polarizer and the transmission axes of the analyzer.

## 24. Huygens principle

1. Each point on a wavefront is a source of secondary disturbance and the secondary wavelets originating from these points spread out in all the directions with the speed of the wave.

2. The new wavefront at any later time is obtained by taking the tangential surface in the forward direction to all the spheres of secondary wavelets.

## 26. Wavefront and types of wavefronts

1. Spherical wave front : It is obtained due to a point source of light.
2. Cylindrical wave front : It is obtained due to linear source of light.
3. Plane wave front : It is obtained with the source of light is at infinity.