IGCSE Physics 0625 Partial Notes

Describe and explain a danger to a driver of not wearing a safety belt during a sudden stop.

1. (Without seat belt, driver:) e.g. keeps moving (forwards)/ does not stop/ has inertia/ has momentum B1 (Driver) hits steering wheel/windscreen/ dashboard

State an instrument that would be suitable to take measurements of a room?

metre rule, tape measure, (surveyor’s) laser measurer, trundle wheel tape is too vague, accept rule(r)

Why is the true pressure at base point of a cylinder with water different from the value calculated

1. There is atmospheric pressure acting on it.

Solar Energy

• Advantages 
  • no polluting gases 
  • Quiet
  • low maintenance 
  • can be placed on roofs 
  • Clean
  • cheap to run 
• Disadvantages
  • intermittent supply 
  • Unattractive
  • takes up space
  • uses land
  • d.c. output

Define internal energy based on atoms

• kinetic energy / potential energy / total energy (of atoms / molecules / particles) 
• Kinetic added to potential energy (of atoms / molecules / particles) 

Explain what is meant by deceleration.

decrease of velocity / speed OR slows / slowing down 

Explain why refractive index does not have a unit

1.  sines have no unit or 
2. sines are ratio of two lengths or 
3. ratio of two speeds (whose units cancel)

How is optic fibres used in communication tecnology?

• information /message / music/sound / signal / data (encoded as pulses of light) sent
• light (travels along fibre) or infra-red (radiation) 
•  light detected (at far end) or message decoded or total internal reflection mentioned 

Precautions while handling radioactive isotopes

• (distance): tongs /manipulator/ centre of cardboard box 

• (absorption): lead gloves / suit/lead glass screen / googles /glasses 

• (time): limit exposure time / keep in box until needed / film badge 

While the boot is in contact with the ball, the ball is no longer spherical. State the word used to describe the energy stored in the ball.

Elastic (energy) OR strain (energy)

Define Weight

(Weight is) force/pull of gravity (acting on an object) 

A 240 V, 60 W lamp is connected to a 240 V supply. The lamp has a constant temperature. State (i) the rate at which the lamp transfers energy to the surroundings

1. 60W

(ii) the names of the thermal processes by which the lamp transfers energy to the surroundings.

1. Radiation and convection

Explain what the maximum temperature here is:

• Radiation mentioned 
• Higher reading or rises faster on thermometer A 
• Black (surface) is a good/better emitter (than polished surface) OR polished (surface) is a poor/bad/worse emitter (than black surface)