mock mistakes

• explain how a balloon reaches terminal velocity: the balloon reaches terminal velocity when there is no resultant force acting on it, weight is greater than drag, resultant force causes acceleration.
• state the name of the wave responsible for the path of ray of light as it passes from air into optical fibre: refraction
• explain the path of the ray of light as it travels through the optical fibre: total internal reflection because core has higher refractive index than air, because angle of incidence is greater then critical angle
• describe how a loudspeaker produces sound: there is an alternating force on the cone, causing the cone to vibrate, cone forces air to vibrate, longitudinal wave formed
• give a reason why there is a net transfer of energy from the outside of the box to the inside of the box during transportation in a hot country: temperature outside the box is greater than the temperature inside the box
• explain how the box is designed to reduce energy transfer by conduction: cardboard is a poor conductor, thicker objects conduct slower
• explain how the box is designed to reduce energy transfer by convection: particles cannot move around, lid reduces convection current forming
• explain why there is an alternating current in the gold ring: changing magnetic field, gold ring cutting field lines, induced voltage for gold ring
• explain how alternating current in the receiving coil causes a sound to be emitted from the loudspeaker: magnetic fields interact in a loudspeaker, causing a force on loudspeaker cone, alternating current causes changing force direction
• state the role of the moderator in a nuclear fission power station: reduce kinetic energy of neutrons
• describe the difference between contamination and irridation: contamination is when non radioactive object comes into contact with a radioactive material. irradiation is when radiation is present
• state where nuclear fission occurs naturally: in stars
• explain the conditions required for nuclear fusion: high temperature to increase kinetic energy of nuclei, high pressure
• describe an experiment that could demonstrate that a sponge pad is charged: bring pad near another uncharged insulator, attraction used to demonstrate charge
• describe the difference between a neutral sulfur particle and a positively charged sulfur particle: neutral have the same number of protons and electrons, positive particle have more protons then electrons