1P Jan 2012 Flashcards
How can you make a measuring cylinder more accurate?
Avoid parallax errors and put cylinder on flat surface.
How can you make electronic scales more accurate?
Put on stable surface, check zero.
To find the density of water what should you keep constant and why?
Temperature, affects volume of water.
What is refraction?
Change in direction of waves at a boundary.
When plotting a graph to find the refractive index what goes against what?
Sin i against sin r
Uniform magnetic field?
Two permanent magnets, north facing south, not touching.
How does a sound wave move through the air?
Vibration of particles, longitudinal. Direction of vibration and propagation are parallel.
Why does the temperature of water reach a steady value?
Rate of energy loss = rate of energy supply.
Advantages of series circuit?
Fewer wires, lower resistance values.
Disadvantages of series circuit?
One fails circuit fails, no independent control.
How do microwaves cook food?
Microwaves are electromagnetic waves which penetrate a few centimeters into the food and cause water molecules to vibrate more.
How does an induction oven work?
Electromagnetic conduction. Coil creates magnetic field which cuts through metal pan. Induces a voltage in the pan causing a current in the pan. Current makes pan get hot which heats water by conduction which convects energy to potato.
