If copper and silicon are cooled from 300 K to 60 K, then the specific resistance will:
1.  Decrease in copper but increase in silicon
2.  Increase in copper but decrease in silicon
3.  Increase in both
4.  Decrease in both

The specific resistance of a conductor increases with:

A 6-volt battery is connected to the terminals of a three-metre-long wire of uniform thickness and resistance of 100 ohms. The difference of potential between two points on the wire separated by a distance of 50 cm will be:

1. 3 V

2. 1 V

3. 1.5 V

4. 2 V