physics

1. what is not a reasonable estimate of the physical property indicated?
a 2.x 10°w for the power dissipated by the heating element of an electric kettle
b 4x 10?m* for the volume of water in a swimming pool
c 5.x 10°ns for the momentum of a lorry moving along a road
d 6x 10?n for the weight of a fully grown racehorse

2 which quantity could have units of nmv~"?
a acceleration
b_ charge
cscurrent
d_ resistance

3 an object is acted upon by two forces, 10n in the vertical direction and 6n at 40° to the vertical,
as shown.
10n
'40°\.6n
what is the resultant force acting on the object?
a b cc d
15n 15n

155 18°

j ean : 6.6n

137° 136°

4 an analogue ammeter with a range of 0—-250ma is connected into an electrical circuit. the
diagram shows the ammeter’s display.
5
\ wu 7,
9 s a <a)
what is the reading on the ammeter?
a 76ma b 165ma c 183ma d 190ma

23 students take readings of the volume of a liquid using three different pieces of measuring
equipment x, y and z.
the true value of the volume of the liquid is v.
the students’ results are shown.
x ba z
ey ee ye

6 which graph shows the variation with time t of the velocity v of an object falling vertically
downwards in a vacuum?
a b
vv v
0 0
0 t 0 t
cc d
0 0
0 t 0 t

8 a book of weight w is at rest on a table. a student attempts to state newton’s third law of motion
by saying that ‘action equals reaction’.
book
es
ct
if the weight of the book is the ‘action’ force, what is the ‘reaction’ force?
a __ the force w acting downwards on the earth from the table
b_ the force w acting upwards on the book from the table
c_ the force w acting upwards on the earth from the book
d_ the force w acting upwards on the table from the floor

9 four balls are dropped at the same time from the top of a very tall tower. there is no wind
blowing.
which ball hits the ground first?
a b cc d
mass m mass 4m mass m mass 4m
diameter d diameter d diameter 2d diameter 2d

10 a nitrogen molecule p travelling at a speed of 320ms™ in a vacuum collides with a stationary
nitrogen molecule q.
after the collision, p travels at a velocity of 180 ms“ at an angle of 55° to its original path.
q travels in a direction at an angle of 34° to the initial path of p.
4180ms"
320ms" ass:
e @ “ss. [342
on’
before collision after collision

assume that there are no external forces acting on the molecules.
what is the magnitude v of the velocity of q after the collision?
a 120ms‘ b 140ms™ cc 180ms' d 260ms™

11 acharged particle is placed in a uniform field of force. the direction of the force on the particle is
opposite to the direction of the field.
what is the field and what is the charge on the particle?
a electric negative
b electric positive
cc gravitational negative
d gravitational positive

12 a disc of radius ris acted upon by two opposite forces, each of magnitude f. the forces form a
couple, as shown.
fe
f )
what is the torque of this couple?
a fr b fr c 2fr d 4fr

13 a uniform square sign of weight 40n is suspended vertically from its top edge by a horizontal
hinge, as shown.
front view side view
hinge hinge
sign i
0.80m sign
0.80m
the hinge is not frictionless. when the sign is displaced from the vertical by an external force and
then released, it does not return to the vertical position.
the maximum torque exerted by the hinge on the sign is 6.0n™m. the sign is displaced by 90° so
that it is horizontal and then gradually released.
at which angle to the vertical does the sign hang after release?
a 11° b 22° cc 68° d 79°

14 each foot of an elephant has a circular cross-section with a circumference of 1.4m. the elephant
has a mass of 5400 kg.
the elephant is standing still with all four feet on the ground. assume the pressure under each
foot is the same.
what is the approximate pressure exerted on the ground by each of the elephant’s feet?
a 8.7kpa b 35kpa c 85kpa d 340kpa

15 astone is falling vertically through the air at a constant (terminal) velocity.
which energy change is occurring?
a gravitational potential energy to thermal energy
b_ gravitational potential energy to kinetic energy of the stone
c_ kinetic energy to gravitational potential energy of the stone
d_ kinetic energy of the stone to thermal energy

16 an object of weight 12n rests on a platform on top of a container with two pistons, as shown. the
container contains a fixed mass of gas, and the pistons are free to move.
object
platform
piston
piston
plunger container
the plunger is slowly pushed 4.0cm to the right. as a result, the object slowly moves upwards a
distance 0.50 cm.
how much work is done on the object?
a 0.060j b 0.48j c 6.0j d 48j

17 aconstant force f, acting on a car of mass m, moves the car up a slope through a distance s at
constant velocity v. the angle of the slope to the horizontal is a.
s oed
é sf
soa
‘ f
_——~—s
ag
s@)
the acceleration of free fall is g.
what is the ratio gravitational potential energy gained by car 5
work done by force f :
mgs sina mv mv? mg sina
a b— c db ———
fv fs 2fs f

18 what is the definition of power?
a power is the product of force and velocity.
b_ power is the product of force and work done per unit time.
c_ power is the product of force per unit time and velocity.
d_ power is the rate at which work is done.

19 asteel bar of circular cross-section is under tension 7, as shown.
the diameter of the wide portion is double the diameter of the narrow portion.
ie | id t
whatisthe value of stress in the wide parien 2
stress in the narrow portion
a 0.25 b_ 0.50 cc 2.0 d 4.0

20 two guitar strings are stretched by tensile forces.
string x is stretched by a tensile force f that causes an extension x.
string y is stretched by a tensile force 2f that causes an extension 2x.
the strings obey hooke’s law.
whatiethe ratio sian energy in stretched srintg x 2
strain energy in stretched string y
a 4 b 2 c i d 1

21 two lasers emit light ina vacuum. one laser emits red light and the other emits green light.
which property of the light from the two lasers must be different?
a amplitude
b_ frequency
c intensity
d_ speed

22 two particles in a progressive wave are a distance 10cm apart. the two graphs show the
variation with time t of the displacement d of the two particles.
d d
0 0
t 0 t
what could be represented by the two graphs?
a particles in a longitudinal wave with a compression and the nearest rarefaction separated by
10cm
b particles in a longitudinal wave with a compression and the nearest rarefaction separated by
20cm
c particles in a transverse wave with a peak and the nearest trough separated by 20cm
d particles in a transverse wave with two adjacent peaks separated by 10cm

23 a sound wave is detected by a microphone that is connected to a cathode-ray oscilloscope

(cro).

the screen of the cro displays a waveform, as shown.
kt i alta | la
wt tan tf ti |
ty tt
lwt a ttt nt ft
buaav annie
lmt iy ttt i

the time-base is set to 20 :sdiv™.

what is the frequency of the sound wave?

a 15hz b  15000hz c 20000hz d 30000hz

24 a person stands at the side of a straight railway track. a train moves towards the person and
emits sound from its whistle. the person hears a sound of frequency 1690hz as the train
approaches him.

the person then hears sound of frequency 1500hz as the train moves away from him. the
speed of sound in air is 340ms™.

what is the speed of the train?

a 20ms™ b 38ms" cc 41ms* d 43ms‘

25 which list shows electromagnetic waves in order of decreasing frequency?
a gamma-rays —> infrared —> ultraviolet > radio waves
b gamma-rays — ultraviolet > infrared > radio waves
c_ radio waves —> infrared > ultraviolet > gamma-rays
d_ radio waves -> ultraviolet > infrared > gamma-rays

26 a pipe of length l is open at one end and closed at the other end. a loudspeaker is at the open
end and emits a sound wave into the pipe.
pipe
, :
7 l y
loudspeaker
when a stationary wave is formed, there is an antinode at the open end of the pipe.
which wavelength of sound could be used to produce a stationary wave?
a 2 bl e 4 d 2l
3 3

2/ which diagram best shows how water waves diffract when they pass through a gap in a barrier?
a b
gap | |
barrier
c d
: ) :

28 ina two-source interference experiment, light of a single frequency is incident on a double slit.
the light waves emerging from the slits are coherent.
what is meant by coherent?
a the waves are in phase.
b_ the waves have a constant phase difference.
c_ the waves have the same amplitude.
d_ the waves interfere constructively wherever they overlap.

29 a parallel beam of light consists of light of wavelength 420 nm and light of wavelength 630 nm.
the light is incident normally on a diffraction grating.
the diffraction maxima for the two wavelengths overlap only at an angle of 31° from the direction
of the incident light beam.
what could be the line spacing of the diffraction grating?
a 1.2um b 1.6um c 2.4um d 3.7um

30 a positively charged particle p is in an electric field, as shown.
y
° xx |
z
the field lines (lines of force) are evenly spaced and parallel.
which statement is correct?
a moving p a small distance in any direction will not change the electric force on p.
b moving p a small distance in direction y will increase the electric force on p.
c moving p a small distance in direction z will increase the electric force on p.
d moving p a small distance in direction x will increase the electric force on p.

31 the diagram shows two parallel metal plates p and q, separated by a distance of 5.0mm. there
is a potential difference of 700 v between the plates. plate q is earthed.
-700v
plate p
5.0mm er
plate q
= ov
what is the magnitude and direction of the electric field at point r?
a 1.4.x 10?nc™ from p towards q
b  1.4x 10°nc from q towards p
c 1.4 x 10°nc™ from p towards q
d 1.4.x 10°nc™ from q towards p

32 a wedge-shaped metal conductor of length l, varying width and uniform thickness is connected
to a cell, as shown.
4
x
a
l
which graph best shows how the average drift velocity v of electrons in the conductor varies with
distance x from end x?
a b cc d
v | vv v | vv |

33 the power output of an electrical supply is 2.4kw at a potential difference (p.d.) of 240v. the
two wires between the supply and a kettle each have a resistance of 0.50, as shown.
supply kettle
0.500
240v
2.4kw oe
0.500
what is the power supplied to the kettle and what is the p.d. across the kettle?
| | power/kw p.d./v
a 2.3 230
b 23 235
cc 2.4 230
d 24 235

34 the graph shows the variation with potential difference v of the current j in components x, y
and z.
i xx
z
ng
0
0 vv
which row correctly identifies the components?
metallic conductor at | semiconductor filament
constant temperature diode lamp
a xx z y
b y xx z
cc y z x
d z y x

35 awire of resistance 9.55 q has a diameter of 0.280 mm.
it is made of metal of resistivity 4.90 x 10-7 qm.
what is the length of the wire?
a 1.20m b 4.80m cc 19.0m d 76.0m

36 a cell of constant electromotive force (e.m.f.) but with internal resistance is connected to a fixed
resistor r using a potentiometer. a voltmeter measures the potential difference (p.d.) between
the terminals of the cell.

z

r

which statement explains the change to the reading of the voltmeter as contact z is moved
towards end x of the potentiometer?
a_ the voltmeter reading decreases because the current through the cell decreases.
b_ the voltmeter reading decreases because the current through the cell increases.
c_ the voltmeter reading increases because the current through the cell decreases.
d_ the voltmeter reading increases because the current through the cell increases.

37 acell of electromotive force (e.m.f.) e and negligible internal resistance is connected to a circuit.
the circuit has currents i,, iz and iz, and potential differences v;, v2 and v3, as shown.
e
v,
l, i, «=e.
v, [j
sn al
—
=p
[|
i;
which equation represents a statement of kirchhoff's first law?
a l=h+k b h=h=k c e=vi+ v2 dv; = v2 = v3

38 two resistors are connected in series with a 6.0 v power supply, as shown.
+6.0v
r
12kq
ov
what is the resistance of the variable resistor r to give a potential difference of 1.0 v across the
12 kq resistor?
a 2.0kq b 10kq c 60kq d 72kq
ls ee eee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee————ee—e—— — ——e

39 a nucleus of magnesium decays into a nucleus x by emitting a b particle. the decay is
represented by the equation shown.
i2mg > ox + {bp
what are the values of p and q?
a 22 11
b 22 13
cc 23 11
d 23 13

40 inf decay, a neutron inside a nucleus changes to a proton.
which statement describes the quark composition of the nucleus during the decay?
a the number of down quarks decreases by one.
b the number of down quarks increases by one.
c the number of down quarks stays the same.
d the number of up quarks stays the same.

Solve 9702_s21_qp_12