Why is the use of ac voltage preferred over dc voltage ? Give two reasons.
Any two of the following (or any other correct) reasons :
(i) ac can be transmitted with much lower energy losses as compared to dc.
(ii) ac voltage can be adjusted (stepped-up or stepped down) as per requirement.
(iii) ac current in a circuit can be controlled using (almost) wattless devices like choke coil.
(iv) ac is easier to generate.
(i) ac can be transmitted with much lower energy losses as compared to dc.
(ii) ac voltage can be adjusted (stepped-up or stepped down) as per requirement.
(iii) ac current in a circuit can be controlled using (almost) wattless devices like choke coil.
(iv) ac is easier to generate.
Obtain the expression for the energy density of magnitude field B produced in the inductor.
Show that the current leads the voltage in phase by in an ac circuit containing an ideal capacitor.
Show that in the free oscillations of an LC circuit, the sum of energies stored in the capacitor and the inductor is constant in time.
In electric arc furnace Cu or Iron is melted due to variation of
(a) current
(b) magnetic field
(c) voltage
(d) electric field
Give an example of a material each for which temperature coefficient of resistivity is:
(i) positive, (ii) negative.
Why should electrostatic field be zero inside a conductor ?
A charge ‘q’ is moved from a point A above a dipole of dipole moment ‘p’ to a point B below the dipole in equatorial plane without acceleration. Find the work done in the process.
Two equal balls having equal positive charge ‘q’ coulombs are suspended by two insulating strings of equal length. What would be the effect on the force when a plastic sheet is inserted between the two ?
A point charge Q is placed at point ‘O’ as shown in figure. Is the potential at point A, i.e., , greater, smaller or equal to potential, at point B, when Q is (i) positive, and (ii) negative charge?