Questions Corrections 2018 Flashcards
Two sources of inaccuracy for the investigation to determine the spring constant of a spring
Not fixing the ruler in position (with a clamp stand and boss) but simply holding it next to the spring
Not clamping the ruler vertical
Why does the movement of a bar magnet induce a potential difference across the coil
Magnetic field lines cut by the coil (generator effect)
Suggest two changes to the design of the seismometer that would make it more sensitive to small vibrations
Increase magnetic field strength
Increase more turns on the coil
Suggest what the student may have done during the investigation to cause each angle of reflection to have a range of values
Not replacing ray box In the same position
What extra evidence could be collected to support the students conclusion that for a plane mirror the angle of incidence is equal to the angle of refraction
Results could be collected for angles of incidence not yet measured
State one change the student should make to the apparatus if he wants to investigate diffuse reflection
Replace the mirror with an irregular reflecting surface
What’s an example of Newtons third law of motion
A boat propeller pushes water backwards, the boat moves forwards the force on the water causes an equal and opposite force to act on the boat
Explain why the velocity of the satellite changes as it orbits the Earth
Gravity causes satellite to accelerate towards earth
The acceleration causes a change in direction
Velocity changes as direction changes
What is a scientific model
An idea used to explain observations and data
Why do scientists have different models like the wave and particle models of light
Different models may be appropriate in different situations
Explain why scientists replace an old scientific model with a new model referring to a physics model
New evidence
Evidence cannot be explained using the existing model
New model explains new evidence
Such as nuclear model of the atom replacing the plum pudding model
Explain why refraction happens at the boundary between deep water and shallower water
Speed is slower in shallower water
So edge of wave entering shallow water slows down
But the part of the wave in the deeper water continues at a higher speed (so change in direction of the wave fronts)
What is the same as 4 microtesla
4 x 10(to the power of minus six)
When there is a current in the coil the coil rotates continuously
Why?
The sides of the coil experience a force in opposite directions
The forces cause moments that cause the coil to rotate
The two halves of the commutator swap from one brush to the other
The commutator reverses the current (keeping coil rotating)
