Ans. No , the amount of positive and negative charge in any elementary volume remains the same though the electrons are in motion . So a current carrying conductor is electrically neutral .
Ans : When the plastic parts is removed , the capacitance of the metal dies decreases but the charge (developed by friction ) remains unchanged and so the voltage increases in compliance with the formula Q = CV
Ans : The field inside is zero (there is electrostatic screening )
Q . An electron moves along a metal tube with variable cross – section . How will its velocity change when it approaches the neck of the of the tube ?
Ans : Positive induced charges will appear on the neck of the tube and accelerate the electron
Ans : It will stick readily to the conducting wall because the same amount of charge is induced on the wall . But on the insulating wall , less amount of charge is induced . Due to greater force of attraction , it will stick more readily to the conducting wall.
Ans : No , We can not test an electric field by any charge . The test charge should so small that the distribution of the prime charge on the carrier conductor remains unaffected .