Electric Current in Conductors Physics - Electric Current in Conductors

In an electric circuit containing a battery, the charge (assumed positive) inside the battery:

1. Always goes from the positive terminal to the negative terminal.
2. May go from the positive terminal to the negative terminal.
3. Always goes from the negative terminal to the positive terminal
4. Does not move.

A current passes through a wire of non-uniform cross-section. Which of the following quantities are independent of the cross-section?

1. The charge crossing in a given time interval.
2. Drift speed.
3. Current density.
4. Free-electron density.

A resistor of resistance R is connected to an ideal battery. If the value of R is decreased, the power dissipated in the resistor will:

1. Increase.
2. Decrease.
3. Remain unchanged.

Two non-ideal batteries are connected in parallel. Consider the following statements:

1. The equivalent emf is smaller than either of the two emfs.
2. The equivalent internal resistance is smaller than either of the two internal resistances.

1. Both A and B are correct.
2. A is correct but B is wrong.
3. B is correct but A is wrong.
4. Both A and B are wrong.

Identify the correct options:

1. An ammeter should have small resistance.
2. An ammeter should have large resistance.
3. A voltmeter should have small resistance.
4. A voltmeter should have large resistance.

Would you prefer a voltmeter or a potentiometer to measure the emf of a battery?

Is work done by a battery always equal to the thermal energy developed in electrical circuit? What happens if a capacitor is connected in the circuit?

One of your friends argues that he has read in the previous chapters that there can be no electric field inside a conductor. And hence there can be no current through it. What is the fallacy of this argument?

The thermal energy developed in a current-carrying resistor is given by U = i² Rt and also by U = Vit. Should we say that U is proportional to i² or i?

A fan with copper winding in its motor consumes less power as compared to an otherwise similar fan aluminium winding. Explain.

A bulb is made using two filaments. A switch selects whether the filaments are used individually or in parallel. When used with a 15V battery, the bulb can be operated at 5W, 10W or 15W. What should be the resistances of the filaments?

Find the equivalent resistance of the network shown in figure. between the points a and b.

Can the potential difference across a battery be greater than its emf?

A proton beam is going from east to west. Is there an electric current? If yes, in what direction?

How many time constants will elapse before the power delivered by a battery drops to half of its maximum value in an RC circuit?

How many time constants will elapse before the current in a charging RC circuit drops to half of its initial value? Answer the same question for a discharging RC circuit.

The potentiometer wire AB shown in figure. is 50cm long. When AD = 30cm, no deflection occurs in the galvanometer. Find R.

Find the currents through the three reaiators shown in figure.