Multiple choice Flashcards
1
Q
What makes sound travel faster?
A
Particles more closer together.
2
Q
- What happens to the wavelength and frequency of sound when it travels from the air into the water?
A
Wavelength increases. Frequency stays the same.
3
Q
- What is the speed of sound?
A
330-350 m/s
4
Q
- The circuit symbol for a fuse?
A
rectangle with wire through
5
Q
- Which type of transformer is used at the power station prior to connection to the power lines and
which type is used prior to delivery to the houses?
A
prior to powerlines:
step-up
prior to houses:
step-down
6
Q
- Rutherford’s experiment.
What does this provide evidence for?
A
There is a tiny nucleus in each atom; the atom is mostly empty space.
The nucleus is positively charged.
Most of the mass is concentrated in the central nucleus.
7
Q
Define slip ring, split-ring commutator and commutator.
A
slip-ring = a.c generator, to an from coil
split-ring commutator= d.c motor,to and from coil, reverses current in coil when it becomes perpendicular to field
commutator= d.c motor or generator, to and from coil
8
Q
pppppp Speed of light is the same, so the time must be…
A
the same.
9
Q
- Calculating half-life when there is background radiation
A
minus background, divide by two, add background
10
Q
- A rule to remember while working with moments?
A
Direction of arrows determine whether they belong to clock-wise or anti-clockwise.
Try to work at the ends
11
Q
- When pollen grains in water are viewed through a microscope, they are seen to be in continuous,
rapid random motion.
What causes a pollen grain to move in this way?
A
uneven bombardment on different sides by water molecules
12
Q
- Which points are the fixed points of the liquid-in-glass thermometer shown?
A
the points marked 0 °C and 100 °C
13
Q
- He asks the class why the cup is so good at keeping a hot drink warm. Three suggestions are
made.
1 It contains air which is a poor thermal conductor.
2 The air is trapped in tiny bubbles so very little convection is possible.
3 The plastic is a poor thermal conductor.
A
All 3
14
Q
- Longitudinal waves Vs Transversal waves plus examples
A
Longitudinal= wave in which the vibration is forward and back , parallel to the direction of propagation of the wave >P-waves and sound waves
Transversal= wave in which the vibration is at right-angles, to the direction of propagation of the wave >S-waves, electromagnetic waves and water waves
15
Q
- A converging lens can be used as a magnifying glass.
What will be the nature of the image?
A
virtual, upright, enlarged
16
Q
- A quieter sound of the same frequency is made.
What will happen to the number of particles in a region of rarefaction and in a region of
compression?
A
Less particles in compression, more in rarefaction
17
Q
- Examples of hard and soft magnetic materials as well as magnetic materials in general
A
hard- hard steel
soft- soft iron
magnetic- iron, steel, nickel and cobalt
18
Q
- Equation to do with transformers, turns on coils and voltages
A
V^p/V^s=N^p/N^s
19
Q
- The diagram shows the path followed by α-particles as they pass between two charged plates.
They are deflected downwards.
+++++++++
–––––––––
α-particles
β-particles
What happens to β-particles passing through the same electric field?
A
Deflected upwards and deflected more than alpha particles. Gamma is not deflected because they are uncharged.
20
Q
What is acceleration of free fall/acceleration due to gravity?
A
the acceleration of an object falling freely under gravity
21
Q
If a 5kg ball and a 1kg ball fell, which would first land?
A
Both. Acceleration is the same because Earth pulls with the same force on every kg of matter.
22
Q
How does the gravitational field change throughout Earth?
A
Does not change. Uniform gravitational force.
23
Q
What can affect an object’s acceleration?
A
Air resistance
24
Q
What is terminal velocity?
A
the greatest speed reached by an object when moving through a fluid
25
Describe the adventure of a parachutist until terminal velocity.
A free-fall parachutist jumps out of the aircraft and accelerates downwards. Air resistance has little effect at first, but increases with the speed of the motion. Air resistance eventually balances his weight. He stops accelerating and falls at a steady rate known as terminal velocity.
26
Describe the second part of the parachutists' adventure.
Parachute is opened and so area and air resistance increases; there is a bigger force upwards, the forces are unbalanced, so he slows down. Forces become balanced again: weight=drag.
27
4. Which methods give a comparison of the two masses?
Hang each in turn from the same spring. Compare the extensions.
Place one in the right-hand pan of a beam balance and the other in the left-hand
pan.
28
4. A bicycle braking system transfers energy from a kinetic energy store to an internal energy store.
A motor converts energy from a chemical energy store (battery) to a kinetic energy store.
What enables these energy transfers?
mechanical. electrical
29
4. What is the lowest possible temperature (absolute zero) and what happens to the energy of
particles at this temperature?
–273, particles have least kinetic energy
30
4. Which car shows the greater rate of temperature increase and which car shows the greater rate
of temperature decrease?
both black
(black is a good absorber and good emitter)
(white is a poor absorber and good emitter)
(shiny surfaces reflect light, not good absorber or emitter)
31
4. Which property of the ray of light always remains the same as it moves from air to glass?
Frequency
32
4. What can be said about comets and their orbits?
elliptical and Sun is NOT at the centre of the orbit
33
4. Power source for a stable star?
Fusion, hydrogen
34
4. Which quantity can be determined using the brightness of a supernova in a distant galaxy?
the distance of the galaxy from the Earth
35
An air pistol fires a pellet forwards.
What is the motion of the air pistol?
The air pistol moves backwards with speed less than the pellet. (momentum before and after)
36
3. A crane takes 2.0 minutes to lift a 500 kg load to the top of a building that is 12 m high.
What is the useful power developed against gravity by the crane?
Ep=mg,h
P=W/t
37
3. low specific heat capacity=
less energy required to raise temperature, will end up with a higher temp than an object with higher c
38
4. A student does an experiment to investigate the resistance of a metal wire.
The graph shows the results from the experiment.
(Graph is 'decelerating', resistance on y-axis)
x-axis?
diameter of wire
39
1. A mass is lifted from rest on the ground to Y. There is no air resistance.
P is the increase in gravitational energy of the mass.
Q is the kinetic energy of the mass at Y.
Which expression is equal to the mechanical work done on the mass?
P+Q
40
1. What is the velocity v of the 2.0 kg trolley after the collision?
momentum of 1 + momentum of 2 = momentum of 1 after + momentum of 2 after
41
1. The diagram shows an object moving at a constant speed in a circular path in the direction
shown.
A force acts on the object to keep it in the circular path.
In which labelled direction does this force act, when the object is in the position shown?
inwards to the source
42
1. 2. Which change in the design of a liquid-in-glass thermometer makes it more sensitive?
a larger liquid reservoir
big volume of the bulb
43
1. Thorium 230, 90 decays by alpha particles
226, 88
44
1. The graph shows the measured count rate of radiation from a source containing a radioactive
isotope. The detector is in a laboratory, with no shielding from background radiation. X at point, Y at leveled part.
What is the measured count rate after a time of one half-life?
(X+Y)/2
45
2. A scientist uses an electric motor to lift a load through a vertical distance of 2.0 m.
He then increases the input power to the motor and repeats the experiment. The efficiency of the
motor does not change.
Which row correctly describes the effect that this has on the useful work done lifting the load and
the time taken to lift it?
work done stays the same, time taken decreases
46
2. The waves approach a barrier and pass through the gap in the barrier.
The size of the gap is about larger than the wavelength of the ripples.
The ripples are less curved.
47
2. Wavelength of the wave?
Two big loops, half circles
48
2. Beams of light of the same colour..
have the same frequency
49
2. Light from the Sun reaches the Earth in
8 minutes
50
2. The electromagnetic spectrum in order
RMIVUXG, increasing frequency, decreasing wavelength
51
2. What is ultrasound?
sound waves that are too high-pitched for humans to hear
52
2. The graph shows the current–voltage relationship for a circuit component X.
Current increases normally then steeply.
What happens to the resistance of X and what happens to the temperature of X as the voltage increases?
resistance decreases, temperature increases
53
2. a.c on graph, a.v on graph
up and down half circles, upp and down rectangles
54
2. What is used to detect faults in manufactured goods?
gamma rays
55
2. What is ultrasound used for?
- Sonar: measures the depth of water or to locate an object
- speed in water and time for reflected pulse to calculate depth
- detect flaws inside materials, like in buildings
- in medicine to produce an image, computer analysis of the reflected waves reflected off the boundaries of different materials go through a computer analysis
56
3. How to get the biggest diffraction?
gap size=wavelength size
57
3. Rule for beam of particles in a magnetic field?
Fleming's left hand rule
58
3. When Rutherford bombarded thin gold foil with α-particles, he found that some α-particles were
deflected through large angles.
Which statement explains this deflection?
Explains defelction:
most of the mass is concentrated in the central nucleus
the nucleus is positively charged
Does NOT explain deflection
the atom is mainly empty space
(the nucleus is tiny, evidence?)
59
4. What do cable TVs use?
infrared
60
4. Which change is occurring in a nucleus during beta-emission?
A neutron becomes one proton and one electron.
61
2. A force on the pivot..
No! Do not consider!
62
4. Which statement about a falling object accelerating close to the Earth’s surface is correct?
A The weight of the object is increasing and the force of air resistance on the object is
decreasing.
B The weight of the object and the force of air resistance on the object are of equal magnitude,
but act in opposite directions.
C The weight of the object is constant, but the force of air resistance on the object is increasing.
D The weight of the object is less than the force of air resistance.
C
63
4. A ball of mass 0.25 kg hits a wall at a speed of 16 m / s. It then rebounds back along its original
path at a speed of 12 m / s.
What is the impulse experienced by the ball during its impact with the wall?
momentum before=momentum after
Backwards, so it is negative
64
Which diagram shows what happens when a ray of white light passes through a prism?
enters at an angle, splits (red is almost straight), splits again (moving downwards)
65
6. A 100% efficient step-down transformer has primary voltageVp and primary current Ip.
Which row compares the secondary voltage with Vp and the secondary current with Ip?
Vs less than Vp
Is greater than Ip
66
What is Hubble's Law?
distant galaxies are moving away from Earth with a speed, v, that is proportional to their distance, d, from Earth. v=Hod
67
What is Hubble's constant?
the slope of a graph of galaxy speed against distance; ratio of speed and distance
Ho=v/d
2.2x10^-18 per second
68
The inverse of Hubble's constant is known as?
Hubble's time. Used to estimate the age of the universe.
t^universe= d/v= 1/Ho
t^universe= 1/ Ho= s/hubble's constant value= ..s = .. years
69
Right-hand grip rule
Fleming's left-hand rule
Fleming's right-hand rule
grip- wire, Lenz' law
left-hand- motors
right-hand- generators, electromagnetic induction
70
Motors:
How to change direction of force?
How to increase turning effect?
(change direction, two other) reverse current or field
(increase turning effect, fAct) turns, current field
71
Generators:
How to increase voltage generated?
Have in common?
(increase voltage generated, ratm) turn rapidly, turns, coil bigger area, stronger magnets
(in common) field (magnet//electromagnet), coil (fixed/moving), movement (coil and field)
72
Electromagnetic induction:
How to increase?
Cutting?
(increase, are tm) stronger magnet, wire/coil more rapidly, more turns
(cutting rule) further=smaller, quicker=bigger=more turns
73
An object is falling at its terminal velocity. What can you say about the air resistance and acceleration of the object?
There is air resistance, and the acceleration is zero.
74
A student uses a microscope to observe pollen moving on the surface of water.
Which statement describes the reason for this movement?
Microscopic pollen particles are moved by water molecules.
75
Some hot water is sealed inside a metal can. The can is in a vacuum in outer space. The hot water slowly cools down.
How does the thermal energy escape into space?
by conduction then radiation
76
The Sun emits infrared radiation and light.
Light from the Sun reaches the Earth in 8 minutes. How long does it take infrared to reach Earth?
8 minutes, v=f times wavelength
77
The diagram shows the current–voltage graph for a metal wire. (line straight through origin)
As voltage increases...
the resistance stays constant
78
Make the statement about a transformer.
An a.c in the ....... induces a .... in/across the...
An alternating current in the primary coil induces an alternating voltage across the secondary
coil.
79
Which nuclear reaction powers a stable star?
nuclear fusion of hydrogen nuclei producing helium
80
Which mass, on the Moon, would stretch the spring by the same extension?
(remember spring constant formula)
81
A train is traveling horizontally in a straight line. A book is on a table in the train. It experiences contact force and weight as well as friction.
How is the train moving?
book is not moving at constant speed or is still, because there's no opposite forces of the same magnitude
moves opp direction to frictional force
82
When soft iron is brought near a north pole, what is its induced polarity at its end?
South pole
83
What to remember about a wire and its resistance?
The resistance of the wire is directly proportional to its length and inversely proportional to its
cross-sectional area.
84
What are the charges on the poles? (What Q to remember this for?)
north is negative
south is positive
for generator Q
85
How are positive and negative ions formed from atoms?
lose or gain electrons, protons cannot be lost or gained
86
What background count rate method for which Q?
nonsense for long one (counter reading 1hr later)
regular for shorter one
(what is the count rate for the radioactive source)
