Test 8 completed Flashcards

1
Q

Describe what happens to the velocity of the motorcyclist as she travels around the bend
at constant speed.

A

Velocity changes, as the direction of the motion changes

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2
Q

Explain why there must be a resultant force on the motorcyclist as she travels around the bend.

A

because the velocity changes which needs a resultant force.
resultant force is perpendicular to the motion of the motorfiets

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3
Q

State what happens to the motion of the helium particles as the temperature increases.

A

Move faster

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4
Q

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.

A
  1. Particles collide with more force
  2. particles collide less frequently
  3. larger volume cancels out the effect of increased temperature
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5
Q

The efficiency of the lamp is less than the value determined in (a)(ii).
Suggest one reason for this.

A

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

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6
Q

monochromatic

A

light of a single frequency

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7
Q

Explain why the ray of light does not change direction when it enters the block through side
AB.

A

incident ray is along the normal, so no refraction

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8
Q

All light is reflected back inside the block and hits a side..

A

all light is reflected back inside

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9
Q

State two reasons why microwaves are used for mobile phone (cell phone) signals.

A

(microwaves) only need short aerials / antennas

(microwaves) penetrate (some) walls

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10
Q

Describe, with the aid of a diagram, how a digital signal differs from an analogue signal.

A

analogue- varies over a range of values
digital- consists of two values

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11
Q

State two advantages of using digital signals rather than analogue signals.

A

faster data transmission rate
data transmitted over longer distances
noise easily removed from data

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12
Q

Describe what is meant by a potential divider.

A

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

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13
Q

Define the term half-life.

A

time taken
for number of radioactive nuclei to halve

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14
Q

Explain, in terms of energy transfers, why the speed of Pluto varies in this way.

A

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

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15
Q

Conversion to kelvin?

A

+273

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16
Q

All mobile phone networks use digital signals to communicate with the phone.

Describe, with the aid of a diagram, how a digital signal differs from an analogue signal.

A

labelled diagram of digital (signal) with blocks of high (1) and low (0) AND labelled diagram of analogue with continuously
variable signal going up and down.

digital (signal) consists of two values
analogue (signal) varies over a range (of values)

17
Q

What does bluetooth use?

A

Radio waves for short range communication. Useful for communication between electronic devices such as in a hands free mobile phone system.

18
Q

What electromagnetic radiation do optical fibres (for cable television and high speed internet) use?

A

infrared radiation and visible light

19
Q

Two facts about optical fibres?

A

These waves have higher frequency and can carry more data which is vital for high-speed broadband connections.

20
Q

What to remember when working with circuits?

A

open and closed switches