16. Prove that the current density …

16. Prove that the current density of a metallic conductor is directly proportional to the drift speed of electrons 17. What is internal resistance of a cell? Derive the relation between r, E, V 18. Derive an expression for the capacitance of a paraliel plate capacitor. 19. Derive an expression for the electric potential at a point along the axial line of the dipole.  . Three capacitors of capacitances 2 PF , 4PF, and 3PF are connected in parallel. What is the total capacitance of the combination? 20. Explain the effect of introducing a dielectric slab between the plates of a ll plate capacitor on its capacitance. Derive an expression for its capacitance with dielectric as the medium between the plates. 21. A) State the principle of potentiometer. Draw a circuit diagram used to compare the emf of two cells. Write. the formula used B) How can the sensitivity of a potentiometer be increased? 22. A) Deduce the condition for balance in a Wheatstone bridge. Using the principal of Wheatstone bridge describe, the method to determine the specific resistance of a wire in the laboratory. Draw the circuit diagram and write the formula used. B) Write any two important precautions you would observe while . performing the experiments.

Lota graph showing the variation of current with voltage for the materials gaas on the graph mark the reason where a resistance is negative and Om is obey

A mirror is turned through 17 degree then the reflected ray is turned by

Q.3A Free Proton and a Free Electron are Placed in a Uniform Field. Which of the Two Experiences Greater Force and Greater Acceleration?

Three charges q,-4q,2q are placed at vertex of equilateral triangle find amount of work done to make its set up

Two metallic sphere of radii 1 cm and 3 cm are given charge of minus 1 into 10 ke power 2 coulomb and 5 x 10 power 2 respectively if these are connected by conducting wire the final charge on the bigger sphere is

A Carbon resistor has three strips of red colour and a gold strip. What is the value of resistor? What is its tolerance?

two pith -balls each weighing 10-³ kg are suspended from the same point by means of silk threads -0.5 m long .on charging the balls equally, they are found to repel each other to a distance of 0.2 m .calculate the charge on each ball .

A pith ball may become charge d by gaining or losing

what us current

Derivation of ohm's law class 12