explanations Flashcards
by considering energy,
why is the p.d. < emf of battery
- Emf is total energy available per unit charge
- Energy is dissipated in the internal resistance
explain how a single beam of alpha particles and gamma radiation may be separated
- Electric field is used at an angle to the beam
- Alpha particles will show deflection
- Gamma radiation will show no deflection
conditions for formation if stationary waves
- two waves with the same frequency, wavelength, and speed but in opposite in direction overlap
projectile motion –> why is KE of ball not equal to GPE
- there is KE of the ball when it starts its path
explain how the collision is inelastic but still obeys the law of conservation of energy
- kinetic energy not conserved
- but total energy is conserved
explain the part played by diffraction in the production of the fringes
- when the waves passes the slit, they spread into
geometrical shadows - and interfere
why double-slit used instead of two sources of light
- double slit produces two coherent waves with constant
phase difference
describe 2 diff between Beta- emission and Beta+ emission
- During B- emission, anti-neutrino also emitted,
During B+ emission, neutrino also emitted - During B- emission, neutron changes into proton
During B+ emission, proton changes into neutron
Describe and Explain how the change in KE of Alpha-particles compares with Electrons
- charge of alpha particles is positive, opposite to
electron - KE is reduced
- charge of alpha-praticles is twice than that of electrons,
- KE is twice
By reference to interference,
1. Explain the zero order maximum
- First order maximum
- Waves overlap with phase difference of 0
2. Waves overlap with phase difference of 360
Describe I-V graph of
1. A metallic conductor at constant temp
- A semiconductor diode
- Straight line through the origin
- 0 current for one direction, up to 0 or few tenths of
volts in the opposite direction - straight line with positive gradient
- 0 current for one direction, up to 0 or few tenths of
explain what is it meant by charge is ‘quantised’
charge exists only in discrete amounts.
differences between stationary waves and progressive waves
- -progressive wave transfer energy,
-stationary wave does not - -in progressive wave, all particles have same
amplitude
-in stationary wave, amplitude varies from max to
min/zero - -in progressive wave, adjacent particles are not in
phase
-in stat; adjacent particles are in phase
explain how the motion of the oil drop shows that it is in equilibrium.
- oil drop is in constant speed
- so no Rf
Describe the change to the pattern of the field lines (lines of force) representing the uniform electric field as the potential difference decreases
- separation of field lines increases
conditions for ripple tank waves to be visible
- coherent
- same amplitude
name a piece of equipment to allow waves in the ripple tank to be seen clearly
stroboscope to free the motion of the waves
Explain why an intensity maximum is detected at C
- Path Difference = resultant distance/wavelength = nλ
- Waves are IN PHASE with each other
- Constructive Rnterference takes place with maximum
intensity
Describe how measurements can be taken to determine accurately the cross-sectional area of the wire.
- Using a micrometer,
- measure the diameter of wire
- take several readings along the wire and average
suggest why B- particles are emitted with a range of kinetic energies
- antineutrinos are also emitted
- KE shared with antineutrinos
Explain the origin of upthrust
- there is a difference in pressures on the top and bottom
surfaces of the cylinder - pressure bottom > pressure top
uncertainty of micrometer vs metre rule
micrometer +/- 0.01mm
metre rule. +/- 1mm
angle constant, frictional force constant.
Explain why is it incorrect to assume the total resistive force is constant
- force due to air resistance is not constant
- air resistance ↑ as v ↑
Part of the energy released by the decay is given to the 2 leptons.
State 2 possible forms of the remainder of the energy released.
- KE
- gamma radiation
Describe the energy conversion that occurs when the parcel is falling through the air at constant (terminal) speed.
GPE –> Thermal Energy / internal
when Ar is negligible, why is the horizontal component of velocity of the ball constant.
- force in horizontal direction is zero
Explain why when the card has come to rest, its centre of gravity is vertically below point P
- line of action of weight acts through P
- so weight does not have a moment at P
A greater mass is kicked with the same velocity
State and explain the effect, if any of the increased mass on the max height reached by ball. (Air resistance is negligible)
- no change to max height
- acceleration of ball is unchanged as it is not dependent
of the mass
Explain why a bright fringe is produced at X
- Waves from slit overlap at X
- With phase diff of 0 degrees
- ## Constructive Interference takes place
State 3 quantities that are conserved in the decay
- mass energy
- charge
- proton number
- nucleon number
what is meant by the particles colliding elastically
- total KE before collision = total KE after collision
Suggest why the B- particles are emitted with range of kinetic energies
- anti-neutrinos are also emitted
- energy is shared with anti-neutrinos
