Which of the following statements about quantum tunneling is not ...

[saraeharris]

Which of the following statements about quantum tunneling is not true?
 
  A) It is used in modern electronics and, in fact, our modern-day computers would not work without it.
  B) Although it has been observed to occur, it violates all other known laws of nature and explaining it therefore represents a major challenge to physicists.
  C) It plays a crucial role in nuclear fusion in the Sun.
  D) It allows electrons and other subatomic particles to pass through wall-like energy barriers even when it seems they do not have enough energy to get through the barriers.

Question 2

A novice marksman fires a rifle while holding the butt of the rifle a couple of centimeters away from his shoulder. Explain what happens in terms of the physical principles involved.
 
  What will be an ideal response?

[billybob123]

Answer to Question 1

B

Answer to Question 2

The initial momentum of the bullet/gun system was zero kgm/s, so after firing the rifle the forward momentum of the bullet is equal and opposite to the backward momentum of the rifle alone. The rifle kicks back and hits the marksman on the shoulder with sufficient speed to cause a bruise. An expert marksman would hold the rifle tight against the shoulder. The recoil then involves both the mass of the rifle and the mass of the upper part of the body of the marksman.

[saraeharris]

Excellent

[Jossy]

Great answer, keep it coming