3. Sand has a low specific heat compared to air
Answer:
4 A
Explanation:
The relationship between current, voltage and resistance in a circuit is given by Ohm's law:

where
V is the voltage
R is the resistance
I is the current
The equation can also be rewritten as

from which we see that the current is inversely proportional to the resistance, R.
In this problem, the initial current is I = 8 A. Then the resistance is doubled:
R ' = 2R
So the new current is

so the current is halved.