Physics
When a piece of pure silicon is doped with aluminium, then

The conductivity of the doped silicon piece will remain the same
The resistivity of the doped silicon piece will increase
The doped silicon piece will become n-type
The doped silicon piece will become p-type

ANSWER DOWNLOAD EXAMIANS APP

Physics
It takes much longer to cook food in the hills than in the plains, because

in the hills the humidity is high and therefore a lot of heat is absorbed by the atmosphere leaving very little heat for cooking
n the hills the atmospheric pressure is lower than that in the plains and therefore water boils at a temperature lower than 100oC causing an increase in cooking time
in the hills the atmospheric density is low and therefore a lot of heat is lost to the atmosphere
due to low atmospheric pressure on the hills, the water boils at a temperature higher than 100oC and therefore water takes longer to boil

ANSWER DOWNLOAD EXAMIANS APP