A metallic resistor is connected across a battery. If the number of collisions of the free electrons with the lattice is decreased in the resistor by cooling it, the current will?
The correct option is A Increase
As the resistor is cooled the number of collisions of free electrons with the lattice (i.e. the fixed positive ions) decreases for any given time interval.
What does that mean?
It simply means that the resistance decreases.
Anyway you could have guessed it by the mere fact that the resistor is being cooled. No problem but keep that in mind.
Now as the resistance decreases current must increase.