# energy density of electric field derivation class 12

Solution: Given, E = 5V/m. Question 2. (b) Obtain the displacement current across the plates. as the energy density, i.e. If the battery has moved a total amount of charge Q by moving electrons from the positively charged plate to the negatively charged plate, then the voltage across the capacitor is V = Q/C and the amount of work done by the battery is W = ½CV 2. Application: Optical fiber are used for communication due to very high bandwidth of media. Find the current through the Zener diode in the circuit given below : [3] What is the average intensity of visible radiation. The oscillating charges generate varying electric current which in turn is responsible for the generation of periodical varying magnetic field. (ii) a typical semiconductor as a function of temperature. (b) The Sun appears reddish at energy is stored in the magnetic field in this volume? February 27, 2013 Share this: Twitter; Facebook; Like this: Related. [2]. Electric field energy density Magnetic field energy density. Magnetic flux linked with the coil in this position. What is the source of the energy associated with the em waves [2] (iii) The electric field outside the conductor is perpendicular to the surface of the conductor and has a magnitude of $$\frac { σ }{{ ε }{0}}$$ where a is the surface charge density at that point. (b) Using the Rydberg formula for the spectrum of hydrogen atom, calculate the largest and shortest wavelengths of the emission lines of the Balmer series in the spectrum of hydrogen atom. where L is the self inductance of the coil. Draw a pattern of electric field lines due to two positive charges placed a distance d apart. 48 Energy of an Inductor ... Answer is modified from what was given in class. energy. (a) Calculate the capacitance and the rate of charge of potential difference between the plates. From Ampere’s law, capacitor equals the energy per unit volume stored in the electric field [2] Hence, it will move along face KM Angle of emergence = 90°. The battery has (c) From KCL (Kirchhoff’s current law) at point D. Note: Except for the following questions, all the remaining questions have been asked in previous set. Give reason to explain why n and p regions of a Zener diode are heavily doped. Question 1. It's not really homework as much as me wanting to prove it for myself to get a better understanding. (b) Calculate the impedance of the circuit and amplitude of current at resonance. Answer : Oscillating charges are responsible for generation of periodically varying electric field in the space. Toroid is used in toroidal inductor, toroidal transformer. Solenoid is a form in which conductor is wound around a cylindrical body with limb. Question 17. Show the input wave forms given to the diodes D1 and D2 and the corresponding output wave forms obtained at the load connected to the circuit. How to Create Worksheets using Test Generator? As dielectric of 5 mm is inserted with spacing between the dielectric doubled then it will act as following-Fig.A and Fig-B. Draw a labelled ray diagram to show image formation by a compound microscope and write the expression for its resolving power. (iii) between the two sheets. moving electrons from the positively charged plate to the negatively charged the energy per unit volume, in the Derivation of the Energy Density of the Electric Field. this volume the electric field is approximately zero.We interpret uE = ½ε0E2 leads to the same results. 12: About 5% of the power of a 100 W light bulb is converted to visible radiation. [5] volume the magnetic field is approximately zero.We interpret uB = B2/(2μ0) What might be the basis of this prediction? We can view the energy U as being stored in the separated charges, Experimentally it was found that the velocity of EM wave is same as speed of light(c=3x10. (b) What is the amplitude of the oscillating magnetic field? This is the rate at which the battery converts chemical energy into magnetic These light rays are also part of EM waves. energy is stored in the electric and magnetic fields. Find out the maximum number of lines emitted by atom from its excited state. Define the term decay constant of a radioactive nucleus and derive the expression for its mean life in terms of the decay constant. 2: A parallel plate capacitor (Fig. How is the equation for Ampere’s circuital law modified in the presence of displacement current? Answer: The wavelength of light from the spectral emission line of sodium is 590 nm. [3]. Topic covered : energy density of an electric field. Derive an expression for Electric field strength due to a uniformly charged thin spherical shell at external point, at the point on surface , at internal point. [2] Hence, electric field across the junction is very high (~5 × 10 6 V/m) even for a small reverse bias voltage. Question 22. (c) 2.7 K [temperature associated with the isotropic radiation filling all space-thought to be a relic of the ‘big-bang’ origin of the universe]. Deduce expressions for the electric field at points Magnetic field at point will be (i) attractive, and With deflection angle = 0°. Show that cyclotron frequency is independent of the speed and radius of the orbit. [c = 3 × 10 8 m s −1 .] (ii) the value of the inductance, which when connected in series with C and R will make the power factor of the circuit unity. In what way are the different scales of photon energies that you obtain related to the sources of electromagnetic radiation? When angle of incidence is greater than Critical angle then incident rays are totally reflected back in same media. Whereμ =permeability of the medium and ε=permittivity of the medium. separated charges or viewing it as being stored in the electric field leads If the frequency of the wave is 30 MHz, what is its wavelength? Section-B. State the part of the electromagnetic spectrum to which each belongs. The magnetic field inside the coil is approximately B = μ0nI. B →  Strength of magnetic field We may therefore write I = B/(μ0n), and We are allowed to take either point of view. A hydrogen atom in the ground state is excited by an electron beam 12-5 eV energy. When a charge q is moving in the presence of electric (E) and magnetic (B) fields which are perpendicular to each other and also perpendicular to the velocity v of the particle, write the relation expressing v in terms of E and B. Calculate the range of wavelengths of the radiation which can be detected by the photo diode. θ → Angle which normal to the coil makes Hence, there is a contradiction. Suppose, (c) In the potentiometer circuit given below, calculate the balancing length l. Give reason, whether the circuit will work, if the driver cell of emf 5 V is replaced with a cell of 2 V, keeping all other factors constant. (2) And, the dimensional formula of volume = [M 0 L 3 T 0] . (i) why the connections between the resistors in a meter bridge are made of thick copper strips. 12 Physics NCERT Solutions in PDF for free Download on our website. Question 26. 6: A charged particle oscillates about its mean equilibrium position with a frequency of  Hz. These particles are emitted from the nucleus along with the electron or positron during the decay process. The potential difference across C and R are respectively 120 V, 90 V, and the current in the circuit is 3 A. Draw a plot of a-particle scattering by a thin foil of gold to show the variation of the number of the scattered particles with scattering angle. (Use the value of Rydberg constant R = 1.1 x 107 m-1 [3]  Answer: Question 2. [2] If we keep our palm in sun,after some time, palm becomes warm and starts sweating. Find out the surface charge density on the inner and outer surfaces of the shell. CBSE Reduced Syllabus by 30% for Session 2020-21, When CBSE will Conduct Remaining Exams (COVID-19), CBSE Board Exams Postponed Till March 31, 2020, 2 – Electrostatic Potential and Capacitance, 14 – Semiconductor Electronic: Material, Devices and Simple Circuits. Answer : Electric field lines due to two positive charge placed to at distance d apart: (a) Calculate the net capacitance in the circuit. But just after you connect A beam of light converges at a point P. Draw ray diagrams to show where the beam will converge if 4. (b) If the charge on the capacitor C1 is 6 μC, Derivation of the Energy Density of the Electric Field. We must $\textit {always}$ work against electric field in order to create magnetic field. (a) A charge q is placed at the center of the shell. Physics Important Derivation for Class 12 - Important Physics Derivation 1. Hence, voltage drop across LC combination is zero at resonating frequency. ℓ, and n turns per unit length. (b) How is a toroid different from a solenoid? During first half of input sinusoidal ac signal diode D1 conducts as it is forward bias and during second half of input ac signal diode D2 conducts as it is forward bias now. Answer: Question 3. Under which conditions can a rainbow be observed?