D. Copper and Gold
Copper and gold are used a lot in electrical applications.
Air and wood are insulators and glass is also kinda bad...
Answer:
c. may be accompanied by the sound of explosively expanding hot air, called thunder.
Explanation:
Lightning is a discharge which is due to the reaction between oppositely charged charges in the clouds, or between clouds base and the Earth surface.
The motion of the cloud causes charging of clouds by friction, thus the reaction between opposite charges (jumping of charges from one cloud to another) in the cloud can lead to lightning. Also, oftentimes the bottom of a cloud is negatively charged so that this is attracted to the positive charge on the earth surface. Thus leading to a discharge called lightning.
Thus in the given question, the appropriate option is C. This implies that, lightning may be accompanied by the sound of explosively expanding hot air, called thunder.
Answer:

Explanation:
Let the mass of bullet is m, initial velocity of bullet is vi and c be the specific heat of the bullet.
Kinetic energy, K = 1/2 mvi^2
According to the question, 50% of the kinetic energy is equal to the heat energy absorbed by the bullet.
50% of K = mass of bullet x specific heat x rise in temperature
1/4 mvi^2 = m x c x ΔT

The correct answer to this question is this one:
By definition, if a molecule is composed of two hydrogen atoms and one oxygen atom, that molecule is a water.<span> In fact, the structure of water is written as H20, which signifies that two hydrogen (H) atoms and one oxygen (O) atom make up the molecule.</span>