Physics general Flashcards
difference between compression & rarefaction
compression = region of high pressure / where particles are close together
rarefaction = region of low pressure / where particles are further apart
how does turning the coil induce voltage+
coil cuts magnetic field lines / coil experiences changing magnetic field
formula between energy and heat capacity
energy = mass x capacity x change in temp
unit : J
conduction in solid
thermal energy transferred as energy of atoms // particles vibrate more // vibration passed through metal
why a rotating coil generator produces an alternating current
coil cuts lines of magnetic field // e.m.f induced // each side of coil moves upwards and then downwards // current changes direction every half turn
effect of increasing freq on the time taken for pulse to travel and return
time remains the same bc wave velocity doesn’t change
differences between longitudinal and transverse waves
longitudinal : direction of propagation parallel to direction of oscillation
transverse : direction of propagation perpendicular to direction of oscillation
how does slip rings produce an alternating voltage output from the rotating coil
induced voltage changes every half turn // same side of coil remains connected to same slip ring
why expansion occurs when atoms are heated
atoms have greater vibration // about a fixed point so take up more space - average distance between particles increases
differences between evaporation and boiling
E : at any temp, B : only at boiling point
E : happens at the surface, B : throughout the liquid
E : can occur using the internal energy of the system, B : source of heat
E : produces cooling, B : does not produce cooling
E : slow process, B : rapid process
electromotive force definition
energy/work done per unit charge
why parallel circuit
if one lamp fails the other will still work // still a complete circuit
why does ray lof light stay inside the optical fibre
angle of incidence greater than critical angle // total internal reflection
how does wider tyres reduce the pressure
larger surface area // p = f / a
difference between magnetic properties of iron and steel
iron magnetises quicker , steel magnetises slower
dexcribe the structure of a thermocouple
two different metals // joined together
virtual image vs. real image
R : formed where light rays converge
V : formed from where light rays appear to have diverged from
R : can be formed on a screen
V : cannot be formed on a screen
difference between alternating current and direct current
in DC, electric charge only flows in one direction
in AC, electric chrage changes direction
energy transformation that occurs in the generator
kinetic to electrical // electrical to light
use for think converging lens
magnifying glasses
define equilibrium
no resultant force AND no resultant turning effect
method of determining the volume of an irregular object
immerse in water // measure volume of displaced water
what causes tides
moon
how transformer produces a reading on a voltmeter
alternating potential difference applied to p coil
alternating current flows in the p coil
producews a changing magnetic field in the p coil
s coil experiences a changing magnetic field
produces an alternating potential difference across the voltmeter
