Test 8 completed

Question 1

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

Answer 1

Velocity changes, as the direction of the motion changes

Question 2

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

Answer 2

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

Question 3

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

Answer 3

Move faster

Question 4

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.

Answer 4

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

Question 5

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

Answer 5

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

Question 6

monochromatic

Answer 6

light of a single frequency

Question 7

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

Answer 7

incident ray is along the normal, so no refraction

Question 8

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

Answer 8

all light is reflected back inside

Question 9

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

Answer 9

(microwaves) only need short aerials / antennas

(microwaves) penetrate (some) walls

Question 10

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

Answer 10

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

Question 11

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

Answer 11

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

Question 12

Describe what is meant by a potential divider.

Answer 12

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

Question 13

Define the term half-life.

Answer 13

time taken
for number of radioactive nuclei to halve

Question 14

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

Answer 14

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

Question 15

Conversion to kelvin?

Answer 15

+273

Question 16

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.

Answer 16

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)

Question 17

What does bluetooth use?

Answer 17

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

Question 18

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

Answer 18

infrared radiation and visible light

Question 19

Two facts about optical fibres?

Answer 19

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

Question 20

What to remember when working with circuits?

Answer 20

open and closed switches