Answer:
True. 
Explanation:
A diode, which allows current to flow in one direction only, consists of two types of semiconductors joined together.
A semiconductor can be defined as a crystalline solid substance that has its conductivity lying between that of a metal and an insulator, due to the effects of temperature or an addition of an impurity. Semiconductors are classified into two main categories;
1. Extrinsic semiconductor.
2. Intrinsic semiconductor.
An intrinsic semiconductor is a crystalline solid substance that is in its purest form and having no impurities added to it. Examples of intrinsic semiconductor are Germanium and Silicon.
In an intrinsic semiconductor, the number of free electrons is equal to the number of holes. Also, in an intrinsic semiconductor the number of holes and free electrons is directly proportional to the temperature; as the temperature increases, the number of holes and free electrons increases and vice-versa.
In an intrinsic semiconductor, each free electrons (valence electrons) produces a covalent bond. 
 
        
             
        
        
        
Answer:
0.125 volts
Explanation:
The induced emf can be sufficient to stimulate neuronal activity.
One such device generates a magnetic field within the brain that rises from zero to 1.5 T in 120 ms. 
We need to find the induced emf within a circle of tissue of radius 1.6 mm and that is perpendicular to the direction of the field. The formula for the induced emf is given by :

Where
 is magnetic flux
 is magnetic flux
So,

So, the induced emf is equal to 0.125 volts.
 
        
             
        
        
        
Answer:
This is because the air outside is always cooler than the air inside, so after staying outside your body adapts to the cold air, when you come back inside, the cold air is still in you which makes the room seem warmer.