practical questions Flashcards
describe how to find the percentage uncertainty of two readings added together
total absolute uncertainty / total reading x100
Describe three safety measures to minimise risk of eye damage when using a laser in the lab.
→ switch off laser when not in use
→ prevent reflections
→ don’t look directly into laser beam
State & explain ways to reduce percentage uncertainty in the measurement of the wavelength.
→ increase distance from grating to screen
→ use a higher order spot
→ decreases % uncertainty in fringe spacing
What piece of apparatus can be used to generate a wave on a string?
vibration generator operated by a signal generator
What is the evidence for wave like properties of an electron?
the diffraction of electrons by metal crystals
Describe how to find the percentage uncertainty of two readings multiplied/divided together.
sum of percentage uncertainties
Explain why a fixed resistor is used.
→ to limit the maximum current (when variable = 0)
→ prevents overheating of the cell
Explain how photons are produced by collisions between beta particles and atoms.
→ atoms de-excite by moving to a lower energy level
→ they lose energy by emitting a photon
area under force extension graph?
energy stored
exchange particle for proton-electron collision?
W+
effect of mass on terminal velocity
greater mass = greater terminal velocity
