A diode valve is connected to a battery and a load resistance. The filament is heated so that a constant current is obtained in the circuit. As the cathode continuously emits electrons, does it get more and more positively charged?

In a Coolidge tube, electrons strike the target and stop inside it. Does the target get more and more negatively charged as time passes?

A constant current exists in an inductor coil connected to a battery. The coil is short circuited and the battery is removed. Show that the charge flown through the coil after the short circuiting is the same as that which flows in one time constant before the short circuiting.

The internal resistance of an accumulator battery of emf 6V is 10(Omega) when it is fully discharged,As the battery gets charged up.its internal resistance decreases to 1(Omega) The battery in its completely discharged state is connected to a charger which maintains a constant potential difference of 9 V.Find the current through the battery (a)just after the connections are made and (b) after a long time when it is completely charged.

A capacitor of capacitance 100(mu)F is charged by connecting it to a battery of emf 12 V and internal resistance 2(Omega) . (a) Find the time constant of the circuit. (b) Find the time taken before 99% of maximum charge is stored on the capacitor.

A 2muF capacitor is charged to a p.d. of 60V. The charging battery is disconnected and the capacitor is connected in series with a coil of inductance 10mH, so that LC oscillations occur. What is the maximum current in the coil? Assume that the circuit contains no resistance.

A capacitor of capacitance 12(mu)F is connected to a battery of emf 6.00V and internal resistance 1.00(Omega) through resistanceless leads. 12.0(mu)s after the connections are made, what will be (a) the current in the circuit, (b)the power delivered by the battery ,(c)the power dissipated in heat and (d)the rate at which the energy stored in the capacitor is increasing.

Three identical lamps each having a resistance R are connected to the battery of emf as shown in the figure. Suddenly the switch S is closed. (a) Calculate the current in the circuit when S is open and closed (b) What happens to the intensities of the bulbs A,B and C. (c ) Calculate the voltage across the three bulbs when S is open and closed (d) Calculate the power delivered to the circuit when S is opened and closed (e ) Does the power delivered to the circuit decreases, increases or remain same?

A capacitance C , a resistance R and an emf (epsilon) are connected in series at t=0.What is the maximum value of (a) the potential difference across the resistor, (b) the current in the circuit,(c )the potential difference across the capacitor, (d) the energy stored in the capacitor ,(e)the power delivered by the battery and (f) the power converted int heat.

A coil having an inductance L and a resistance R is connected to a battery of emf epsilon . Find the time elapsed before (a) the current reaches half its maximum value, (b) the power dissipated in heat reaches half its maximum value and © the magnetic field energy stored in the circuit reaches half its maximum value.

A galvanometer with a coil of resistance 120 ohm shows full-scale deflection for a current of 2.5 mA. How will you convert the galvanometer into an ammeter of range 0 to 7.5A? Determine the net resistance of the ammeter. When the ammeter is put in a circuit, does it read slightly less or more than the actual current in the original circuit? Justify your answer