Ce Phy Mock Paper A1 Ans

= 85 m (80 – 90 m)

Q1.  A - ray

(c)

Q2. = 707 N

A

F = 321 N

A (c) When he accelerates upward, it requires a NET upward force. The forces acting on his another foot and hands would A increase. Q3.

 A each A A

(a) Blue: Neutral, Brown: Live, Green and Yellow: Earth (b) Brown (c) When overloading occurs/excess current flows

A

the fuse blows / melts and break the circuit

A (d) Alternating current can be stepped-up and stepped-down rather easily. Q4.

A temperature increases, resistance of thermistor  AT decreases. M +M The potential across the 20.0 Ω resistor increases.

(a)As

A (6-5)/5

=

RT = 4Ω

(c)20

A Ω

/

(24.5

+

20)Ω

*

= 2.7 V

6V A

Q5.

C

C

C

R

C

R

R

C

R

(a) The direction of vibration of particle / disturbance is parallel to / in the same direction as the direction of propagation A /travel of the wave. Q6. (a)

a = v/t = 92.2 ms-2 ( 90 – 93.5 ms-2)

(b)

Maximum = number

=

height = Area of square *

56

/

A  0.6 A

M under the curve A (10 * 0.2) m M

+

at2/2 at2/2 (85)/(10) A

S

M

(b)(ii) (70+20) * 10 = 707 + F sin 37°

ut 2

A

(b)(i) When there is NO NET force acting on a body.

T

=

M A

(a) Vertical component = 550 cos 14° + 200 cos 30°

(b)R /20

Apply s = t2 = t = 4.123 (4 – 4.3)

N

 A – description OR diagram

However, they are opposite in direction as there are actionreaction pair.

Q7. (a) Two sources are coherent if their phase difference  A is constant.  A - arrow A (OR zero phase difference OR in phase) (b) Interference occurs. Along AB, there are alternative constructive and destructive interference occur, corresponded to rise and fall in sound A intensity respectively. M (c)Path difference = ( 70.3 – 68.76 )  Am 1.54m = 2λ  A - ray = There should be constructive interference at P. Q8. A

(c) In the case of collision, strong front part or rear part  Aresults in shorter time of collision. Hence resulting in greater force on the driver and passenger A when they are brought to rest. Q12.

A (a) When current flows in the primary coil, the magnetic field around the primary coils changes as the alternating  Acurrent passing through it changes in magnitude and direction. The secondary coil experiences the change of magnetic  A field produced by the primary coil, there would be an induced e.m.f. across it. M+ A

(b)Input

power = I (240) I = 0.16 A

I 1 V1

= =

Output

power (3.2)

= I2V2  A (12)

(c)Voltage

(b) (c)

A from generator is first stepped-up, so that the current would be stepped-down (as VI – power transmitted = A constant ) As power loss along transmission cable is I 2R where I is the current flow and R is the resistance of transmission  A cable. The power loss can be reduced if current flow is steppeddown before transmission.

The north pole should point into the paper. The resulting force on electron, by LHR, would be downward. A

Q13. + A – circular, increasing separation, arrow

(a)(i) Apply E (200 W)(300s) = (0.54 - 0.36) kg lf lf = = 333333 Jkg-1

 A – dir. of force

200

*

M

=

300

/

mlf

(0.54 – A 0.36)

(a) The iron-core strengthen the magnetic field produced by  Athe coil of wire around it.

(ii) Heat transfer in this case is mainly by conduction. The water molecules on the surface of ice have larger vibrational kinetic energy, they vibrate more vigorously A and collide with the molecules next to them. These molecules gain kinetic energy and vibrate faster after collisions, then heat transfer from the outer  A centre layer of molecules to the inner one and finally to the of ice. M

(b) (i) When the switch is closed, the electromagnet attracts  Athe iron bar. A

(b)(i) E = 840 000J

Q9.

Which then move to the right and hits the gong.  A - compression wavelength λ (ii) When the iron-bar is attracted to the right, the spring  metal A lose contact with the fixed contact. The circuit is open, and the electromagnet no longer attracts A  A - rerarefaction the iron bar, which then springs back to the left. Q10.

A (a) One light year = 3 * 108 * 365 * 24 * 360 = 9.46 * 1015 m A (b) When propellant is expelled, it carries a (backward) A momentum, the rocket gains momentum in the forward direction A and thus accelerates forward. (c) The sail should be silvery-coated to enhance reflection. There would be large change in momentum of photon  and A hence the larger forward momentum gained by the spacecraft.

=

mc∆T

=

(10)(4200)(20) A A (ii) Oil can be heated up in a shorter time, and Energy to heat up oil is smaller than that to heat up  Athe the same mass of water. A (iii) fin-shaped radiator / grooved  surfaces A so that there is larger contact area with surrounding air. A (iv) there is energy required to heat up the radiator  body, OR A there is heat lost to surroundings. Q14. (a) cosmic ray / rocks / power radon fallout / nuclear nuclear weapons testing / atomic bomb

Sun granite station accidents (ANY TWO)

(b) keep a certain distance use tongs keep short time minimum source not pointing to anybody

away to of

from

human hold exposure strength

(ANY TWO) Q11.

A

(a)(i) mu = (0.5)(10) = 5 kgms (to the right) -1

A A (d) All eight points correctly plotted, and a fine smooth of  curve A best fit (c) 120, 60, 30, 15, 0, 0

A (ii) mv – mu = (0.5)(-5) – (0.5)(10) = -7.5 kgms-1 (to the left) A (iii) time of contact = 0.1 s M+ A (iv)F = ∆mv/∆t = -7.5/0.1 = 75 N ( to the left)

(b)

Yes,

the

two

forces

are

the

same

in

magnitude A A

(e)(i) beta radiation will not pass through / stopped by 20 mm thick Al sheet, ( OR the sheet is too thick) A (ii) gamma / X-rays

LAST MINUTE REMINDERS Units and directions are very important. You must know the spellings and usage of the following: 

respectively, corresponds, alternatively (i.e. in turn), in phase, constructive, destructive, path difference, springs back, time of impact or duration of collision, collide, current flows, a force act on a mass, integer, trough, crest, circuit, current, voltage, potential drop, attract, step-up, step-down, heat loss to surroundings, faulty appliance, fault, earthed, open circuit (circuit is open), closed circuit (circuit is closed), strengthen, magnetised, background radiation, cosmic ray, α- partcile, β-particle, γ-ray, ionising radiation, conduction, convection and radiation



loud vs soft (sound) , strong vs weak (signal), high vs low (speed or velocity, voltage), big vs small (current), large vs small (force)



potential drop across a resistor / across AB



current passes through a resistor



joule heating I2R in electricity transmission

And the following concepts: For constructive interference, there would be big crest (crest + crest) and big trough (trough + trough), while for destructive interference, there would be no (little amplitude / energy / intensity – for light and sound) where crest meets trough. Changing magnetic field induce e.m.f. For a heater, there is no such thing as “heat loss to surroundings” A vacuum (flask) reduces radiation, stops conduction and convection And do you know the advantage of using alternating current in mains? Do you know the advantage of high voltage electricity transmission? Do you know the advantage of ring circuit?