Question

A metallic resistor is connected across a battery. If the number of collisions of the free electrons with the lattice is somehow decreased in the resistor (for example, by cooling it), the current will
A) Increase
B) Decrease
C) Remains constant
D) Becomes zero

Answer 1

Hint:An electric current is a stream of charged particles such as electrons or ions moving through an electric conductor. Resistance is opposition to the flow of current. When the resistance of the electric conductor decreases the current in the circuit increases. If the resistance is increased more electrons will collide with each other leading to more flow of electrons.

Complete step-by-step solution: If the number of collisions of the free electrons is decreased then drift velocity of the electron and the ions will increase. Also, we know that current is directly proportional to the drift velocity. As a result, the current flowing in the conductor will increase. The number of collisions between the electrons can be reduced if the electrons motion is slowed down by cooling it.
As fewer electrons collide in the resistor, the effective resistance decreases as compared to the earlier case. As the resistance decreases more and more electrons will flow. This leads to an increase in the flow of current in the circuit. As, we know that electric current flowing in a circuit is inversely proportional to the resistance in the circuit.

Thus, option A is the correct option.

Note:The relation between electric current, voltage and resistance is given by ohm’s law. If we can somehow increase the number of collisions in the circuit, the electric current flowing in the circuit will increase. This can be achieved by a number of factors, for example by increasing the temperature. Remember that the collision is decreased in the resistor and not in the conducting wire.