Physics

Question 1

What is the equation for Work?

Answer 1

force x distance

Question 2

What is the equation for Power?

Answer 2

Work
-------------
Power x Time
or
Power = Force x Velocity

Question 3

What is the equation for Kinetic energy?

Answer 3

K.E. = mv^2 / 2

Question 4

What is the equation for Gravitational Potential Energy (GPE)?

Answer 4

G.P.E. = mass x gravity x height

Question 5

What is the equation for Pressure?

Answer 5

Pressure x Area

Question 6

Why does the pressure of a fluid increase as you go deeper?

Answer 6

because of the gravitational force of all the fluid above that point

Question 7

What is the equation for pressure at depths?

Answer 7

Pressure = height x density x gravity

Question 8

What is the relation between pressure and volume?

Answer 8

The volume of the gas is halved, the pressure is doubled. They are inversely proportional.

P1V1 = P2V2

Question 9

What is the relation between temperature, pressure, and volume?

Answer 9

If the temperature doubles, the pressure and volume pressures. Pressure and volume are directionally proportionate to temperature

Question 10

What are the characteristics of an atom?

Answer 10

• Most of an atom is empty
• The nucleus has a positive charge
• Most of the mass is concentrated at the nucleus

Question 11

What are nuclear fission and fusion?

Answer 11

Nuclear fission: When a large nucleus splits into two nuclei, energy, and neutrons
Fusion: Two nuclei fuse together to form a heavier nucleus and release energy

Question 12

Describe an alpha particle

Answer 12

• Consists of 2 protons and 2 neutrons (same as helium)
• Highly ionizing
• Stopped by a paper or a few cm of air

Question 13

Describe a beta particle

Answer 13

• 1 particle consisting of a single electron
• Medium ionizing effect
• Stopped by a few mm of aluminum or 50 cm of air

Question 14

Describe a Gamma-ray (y)

Answer 14

• Weakly ionizing
• Highly penetrable ( several cm of lead)
• Electromagnetic radiation (no particles)

Question 15

How do alpha particles react to electric and magnetic fields?

Answer 15

Electric fields: Deflected a little towards negative

Magnetic field: Deflected a little in the opposite of beta

Question 16

How do beta particles react to electric and magnetic fields?

Answer 16

Electric fields: Greatly deflected towards positive

Magnetic field: Greatly deflected in the opposite of alpha

Question 17

How do Gamma-rays react to electric and magnetic fields?

Answer 17

No deflection

Question 18

How is radiation detected in a Photographic film, Cloud chamber, and a G-M tube?

Answer 18

Photographic film: The film is white; as it absorbs radiation it turns black

Cloud Chamber: A cloud chamber is a container filled with water vapour, Ionising radiation causes the water vapour to condense and form tracks of the particles

G-M tube: A tube that contains a high voltage wire, the radiation ionises the gas inside and creates a charge to the wire to produce a clicking sound every time radiation is absorbed

Question 19

What is a half-life?

Answer 19

The time taken for the count rate to halve, or for it to lose half its radioactive atoms

Question 20

What are the 3 uses of radioactive materials?

Answer 20

• Medical tracers
• Radiotherapy
• Smoke alarms (Alpha particles)

Question 21

How do smoke alarms work?

Answer 21

Alpha radiation is emitted into the air, reaching a detector completing a circuit, if smoke is present, the alpha particles are blocked and the circuit is broken causing an alarm to go off

Question 22

How is radiation used in sterilization?

Answer 22

Gamma rays are used to kill bugs and parasites

Question 23

What are some safety precautions when using radiation?

Answer 23

• Minimise exposure time
• Keep a distance from the source
• Shielding (e.g. lead)