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:
I believe the answer is A and D.
I am unsure of C.
Distance= Time×Speed
= 1800×1.5
= 2700 m
I am not sure it's right. the question itself is confusing.
A. All natural radiation is at a level low enough to be safe
Answer:
Approximate escape speed = 45.3 km/s
Explanation:
Escape speed

Here we have
Gravitational constant = G = 6.67 × 10⁻¹¹ m³ kg⁻¹ s⁻²
R = 1 AU = 1.496 × 10¹¹ m
M = 2.3 × 10³⁰ kg
Substituting

Approximate escape speed = 45.3 km/s