mock prelim 2012 h2 paper 2

8/21/2019 Mock Prelim 2012 H2 Paper 2

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TEMASEK JUNIOR COLLEGE2012 Mock Preliminary ExaminationHigher 2

CANDIDATENAME

CIVICSGROUP

INDEXNUMBER

PHYSICS

Paper 2 Structured Questions

9646/02

1 hour 45 minutes

Candidates answer on the Question Paper.

No Additional Materials are required.

Write your Civics group, index number and name on all the work youhand in.Write in dark blue or black pen on both sides of the paper.You may use a soft pencil for any diagrams, graphs or rough working.Do not use staples, paper clips, highlighters, glue or correction fluid.

Section AAnswer allquestions.It is recommended that you spend about 1 hour 15 minutes on thissection.

Section BAnswer Question 8.It is recommended that you spend about 30 minutes on this section.

At the end of the examination, fasten all your work securely together.The number of marks is given in brackets [ ] at the end of each of eachquestion or part question.


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Data

speed of light in free space, c = 3.00 x 108m s

-1

permeability of free space, o = 4 x 10-7

H m-1

permittivity of free space, o = 8.85 x 10-12

Fm-1

elementary charge, e = 1.60 x 10-19

C

the Planck constant, h = 6.63 x 10-34

J s

unified atomic mass constant, u = 1.66 x 10-27

kg

rest mass of electron, me = 9.11 x 10-31

kg

rest mass of proton, mp = 1.67 x 10-27

kg

molar gas constant, R = 8.31 J K-1

mol-1

the Avogadro constant, NA = 6.02 x 1023

mol-1

the Boltzmann constant, k = 1.38 x 10-23

J K-1

gravitational constant, G = 6.67 x 10-11N m2kg-2

acceleration of free fall, g = 9.81 m s-2

Formulae

uniformly accelerated motion, s = ut + at2

v2 = u

2+ 2as

work done on/by a gas, W = p V

hydrostatic pressure, p = gh

gravitational potential,

f =

Gm

r-

displacement of particle in s.h.m., x = xosint

velocity of particle in s.h.m., v =vocos t = ( )22 xxo -w

resistors in series, R = R1+ R2+

resistors in parallel, 1/R = 1/R1+ 1/R2+

electric potential, V = Q / 4 or

alternating current/voltage, x = xosint

transmission coefficient, T = exp(-2kd)

where k =( )2

2

8 m U E

h

p -

radioactive decay, x = xoexp(-t)

decay constant, =

21

693.0

t


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Section A

Answer allthe questions.It is recommended that you spend about 1 hour 15 minutes on this section.

1 (a) Newton realised that forces always act in pairs and from this idea he developed

the 3rdlaw of motion. State Newton s 3rdlaw of motion.

[1]

(b) A skydiver falls towards the Earth. The arrows in the diagram represents the mainforces acting on the skydiver, the Earth and the air. Two are unlabelled. Thediagram is not to scale.

(i) Identify, in the spaces provided, the forces (A) and (D). [2]

(ii) Comment on the effect of force (D) on the Earth.

[2]

(B) Force of air on skydiver(C) Gravitational force of

Earth on skydiver

(A) .

. .

(D) .

. .Earth


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(iii) Explain carefully, referring to the forces involved, why the skydiveraccelerates at the start of his fall and then reaches terminal velocity at somelater time.

[3]

2 Two small charged metal spheres A and B are situated in a vacuum. The distance betweenthe centres of the spheres is 12.0 cm, as shown in Fig. 2.1.

Fig. 2.1

The charge on each sphere may be assumed to be a point charge at the centre of the

sphere. Point P is a movable point that lies on the line joining the centres of the spheres andis distancex from the centre of sphere A.

The variation with distancex of the electric field strength E at point P is shown in Fig. 2.2.


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Fig. 2.2

(a) State the evidence provided by Fig. 2.2 for the statements that(i) the spheres are conductors,

[1]

(ii) the charges on the spheres are either both positive or both negative.

[1]

(b) (i) State the relation between electric field strength E and potential gradient at apoint.

[1]


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(ii) Use Fig. 2.2 to state and explain the distancex at which the rate of change ofpotential with distance is

1. maximum,

[2]

2. minimum,

[2]

3 (a) State Faraday s law of induction.

[1]

(b) A bar magnet is suspended from the free end of a helical spring, as illustrated in Fig.3.1. One pole of the magnet is situated in a coil of wire. The coil is connected in serieswith a switch and a resistor. The switch is open.

Fig. 3.1


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The magnet is displaced vertically and then released. As the magnet passes throughits rest position, a timer is started. The variation with time t of the verticaldisplacement y of the magnet from its rest position is shown in Fig. 3.2.

At time t = 4.0 s, the switch is closed. Use Fig. 3.2 to

(i) state the evidence for the magnet to be undergoing free oscillations during theperiod t = 0 to t = 4.0 s,

[1]

(ii) state, with a reason, whether the damping after time t = 4.0 s is light, critical orheavy,

[2]

(iii) determine the natural frequency of vibration of the magnet on the spring.

frequency = Hz [2]

Fig. 3.2


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(iv) Explain why, after time t = 4.0 s, the amplitude of vibration of the magnet is seento decrease.

[3]

4 A thermistor has resistance 3900 W at 0 C and resistance 1250 W at 30 C. The thermistoris connected into the circuit of Fig. 4.1 in order to monitor temperature changes.

Fig. 4.1The battery of e.m.f. 1.50 V has negligible internal resistance and the voltmeter has infiniteresistance.

(a) The voltmeter is to read 1.00 V at 0 C. Show that the resistance of resistor R is

7800 W.

[1](b) The temperature of the thermistor is increased to 30 C. Determine the reading

on the voltmeter.

reading = V [2]

(c) The voltmeter in Fig. 4.1 is replaced with one having a resistance of 7800W.Calculate the reading on this voltmeter for the thermistor at a temperature of 0 C.

reading = V [2]


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5 (a) Use the band theory to account for the electrical properties of intrinsic semiconductors.

[2]

(b) Fig. 5.1 shows a p-type semiconductor placed in contact with another of n-type.

Discuss the origin of the depletion region and how it helps the p-n junction to act as arectifier.

[4]

p n

depletion layer

Fig. 5.1


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6 The isotopes Radium-224 ( Ra22488

) and Radium-226 ( Ra22688

) both undergo spontaneous

a-particle decay. The energy of the a-particles emitted from Radium-224 is 5.68 MeV andfrom Radium-226, 4.78 MeV.

(a) State what is meant by the decay constant of a radioactive nucleus.

[1]

(b) Suggest, with a reason, which of the two isotopes has the larger decay constant.

[3]

(c) Radium-224 has a half-life of 3.6 days.

(i) Calculate the decay constant of Radium-224, stating the unit in which it ismeasured.

decay constant = [2]

(ii) Determine the activity of a sample of Radium-224 of mass 2.24 mg.

activity = Bq [3]


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7 Many years ago, Johannes Kepler suggested that planet s orbits about the Sun should

follow the relation 2 3T d , whereby Trefers to the period and dthe mean distance from

the planet to the centre of the Sun. This came to be known as Kepler s third law.

A student wishes to test whether Kepler s third law applies to some of the satellites orbitingUranus. The student obtains the data shown in Fig.7.1 for the mean distance d of thesatellite from Uranus and the period T of the revolution of the satellite about Uranus.

Fig. 7.1

The student also included values of lg d and lg T to plot a suitable graph as shown inFig.7.2.

Graph of lg (d/km) against lg (T/days)

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5.2

5.4

5.6

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-0.5 -0.3 -0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5

lg (T/days)

lg(d/km)

Fig. 7.2

Name of satellite d / km T / day lg (d/km) lg (T/day)

Rosalind 69 930 0.558 4.845 -0.475

Belinda 75 260 0.624 4.877 -0.205

Puck 86 010 0.762 4.935 -0.118

Miranda 129 780 1.414 5.110 0.150

Ariel 191 240 2.520 5.282 0.401

Titania 435 840 8.706 5.639 0.940

Oberon 582 600 13.463 5.765 1.129


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(a) Suggest an advantage of plotting a graph of lg d vs. lg Tover a graph of T2 vs.d3.

[1]

(b) Using the graph provided in Fig.7.2 and making suitable calculations, show whetherKepler s third law applies to these satellites.

Working:

[3]

(c) Suggest why the conclusion in (b)may not be valid.

[1]

(d) Observation shows that the satellite Umbriel orbits around Uranus with a period of4.144 days. Use the graph above to estimate the orbital radius of Umbriel.

radius = km [3]

(e) It was reported from another source that the satellite Umbriel has been discovered to

orbit Uranus at a height of 2.8 x 108

km above the surface of Uranus. Comment on thevalidity of this reported height with respect to your calculated answer in (d).

[2]


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(f) Show that the mass of Uranus Mis related to the radius r and period Tof the satellites

by the equation2 3

2

4= p r

MGT

.

[2]

(g) Hence estimate the mass of Uranus using the graph shown in Fig.7.2.

mass of Uranus = kg [2]

(g) Another lg dvs lg Tgraph is plotted using data on the orbital radii and periods of themoons of Jupiter(of different mass). Compare and comment on the values of thegradient and the y-intercept between the two graphs.

[2]


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Section BIt is recommended that you spend about 30 minutes on this section.

8 A student wishes to investigate projectile motion.

A small ball is rolled with velocity v along a horizontal surface. When the ball reaches the

end of the horizontal surface, it falls and lands on a lower horizontal surface. The verticaldisplacement of the ball isp and the horizontal displacement of the ball is q, as shown inFig 8.1.

Fig 8.1

It is suggested thatgq 2= 2pv2

where g is the acceleration of free fall.

Design a laboratory experiment to investigate how q is related top and how v may bedetermined from the results. You should draw a diagram, on page 15, showing thearrangement of your equipment. In your account you should pay particular attention to

(a) the procedure to be followed,

(b) the measurements to be taken,

(c) the control of variables,

(d) the analysis of the data,

(e) the safety precautions to be taken.[12]


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Diagram


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mock prelim 2012 h2 paper 2

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