Em Spectrum

Question 1

Properties of EM

Answer 1

Transverse

Travel at speed of light in vacuum

Question 2

What is radioactive decay

Answer 2

Emission from nucleus

Random spontaneous

Question 3

Nature of alpha radiation and beta

Answer 3

Stream of charged particals

Question 4

Gamma emissions

Answer 4

Electro magnetic wave

Question 5

Radioactive decay equ
Alpha
Beta

Answer 5

-4 and -2

0 and -1

Question 6

Penetrating abilities of alpha

Answer 6

Paper

Question 7

Penetrating abilities of beta

Answer 7

Al foil

Question 8

Penetrating abilities of gamma

Answer 8

Lead

Question 9

Background radiation existence and origin

Answer 9

Big Bang

CMB

Question 10

What does half life do

Answer 10

Decrease over time

Question 11

Meaning of half life

Answer 11

the time taken for the radioactivity of a specified isotope to fall to half its original value.

Question 12

What is nuclear fission caused by

Answer 12

Absorption of neutrons

Question 13

Fission of u-235

Answer 13

the nucleus splits into two smaller nuclei, which are radioactive
two or three more neutrons are released
some energy is released

11H 21H > 32 He

Question 14

Chain reaction ?

Answer 14

The additional neutrons released may also hit other uranium or plutonium nuclei and cause them to split. Even more neutrons are then released, which in turn can split more nuclei. This is called a chain reaction. The chain reaction in nuclear reactors is controlled to stop it going too fast.

Question 15

Fusion of hydrogen forms?

Answer 15

Helium

Question 16

Need for high temperatures in nuclear fusion ?

Answer 16

Both nuclei are positively charged and therefore will repel each other. This is known as electrostatic repulsion. The nuclei have to get very close in order to collide, which is approximately a million millionth of a millimetre. If the nuclei are moving very fast then they can overcome the electrostatic repulsion. The hotter a molecule is, the faster it will move and the more likely it is to collide.