Test 8 completed Flashcards
Describe what happens to the velocity of the motorcyclist as she travels around the bend
at constant speed.
Velocity changes, as the direction of the motion changes
Explain why there must be a resultant force on the motorcyclist as she travels around the bend.
because the velocity changes which needs a resultant force.
resultant force is perpendicular to the motion of the motorfiets
State what happens to the motion of the helium particles as the temperature increases.
Move faster
As the volume of the helium increases, the pressure of the helium remains constant. The temperature increases
Explain, in terms of the particles of helium, how the pressure of the helium remains constant.
- Particles collide with more force
- particles collide less frequently
- larger volume cancels out the effect of increased temperature
The efficiency of the lamp is less than the value determined in (a)(ii).
Suggest one reason for this.
any one from:
temperature change is an underestimate (due to thermal energy losses)
(thermal energy is) transferred from the water (to air / beaker / bench)
energy (other than light) transferred in lamp (filament / glass / internal structure)
(some) water evaporates
monochromatic
light of a single frequency
Explain why the ray of light does not change direction when it enters the block through side
AB.
incident ray is along the normal, so no refraction
All light is reflected back inside the block and hits a side..
all light is reflected back inside
State two reasons why microwaves are used for mobile phone (cell phone) signals.
(microwaves) only need short aerials / antennas
(microwaves) penetrate (some) walls
Describe, with the aid of a diagram, how a digital signal differs from an analogue signal.
analogue- varies over a range of values
digital- consists of two values
State two advantages of using digital signals rather than analogue signals.
faster data transmission rate
data transmitted over longer distances
noise easily removed from data
Describe what is meant by a potential divider.
potential divider shares e.m.f. in proportion to the resistances of the resistors
part of a circuit consisting of two resistors connected in series to obtain a smaller voltage than supplied
Define the term half-life.
time taken
for number of radioactive nuclei to halve
Explain, in terms of energy transfers, why the speed of Pluto varies in this way.
GPE transfers to KE or vice versa
KE transfers to GPE from X to Y AND GPE transfers to KE from Y to X
total (of GPE + KE) energy is constant
Conversion to kelvin?
+273