CCC Yenching College
2001-2002 Mock Examination
S.7 Physics Paper I
Suggested Answer
1.(a)(i)s1
Hz1
(ii)time = s1
(iii)m1+1+1
the position is m from O (upward)
(iv)m s-11
(v)m s-21
(b)(i)s1
Hz1
(ii)Hz
Beat frequency = s
/ Shape 12 cycles 1
2.(a)1
(b)1
1
(c)speed at the bottom = m s-11
By
m s-21
By1
s1
(d)time = s1
(e)(i)h decreased, speed of the ball at the bottom decreased1
time taken increased. 1
The moment of inertia of a hollow ball is larger than that of a solid ball, speed of the ball at the bottom decreased. 1
time taken increased. 1
- (a)
(b)…11
…21
solving the two equation, we have
m s-11
Hz1
(c)
2
(d)s1+1
(e)t becomes larger1
4.(a)(i)the fringe spacing = m1
accept: m
(ii)m1+1
accept: m
(b)(i)
(ii)Double slit pattern is modified / altered by the single slit diffraction.1
(c)(i)(ii)
5.(a)(i)T1
(ii)1
H m-11
(iii)
(b)(i)0.015 – 0.035 m1
Induced emf is greatest when the rate of change of B is greatest.1
i.e. greatest slope.1
(ii)same1
Trying to oppose the flux change. (Lenz’s law) 1
(c)(i)T1
(ii)1
V1
6.(a)(i)Opposition to the passage of a.c.1
(ii)Combined opposition of resistors, capacitors and inductors to the passage of an a.c. 1
(b)(i)V1
V1
(ii)A1
(iii)
H1
1
(c)Capacitors have high reactance at low frequencies1
loudspeaker 1 operates at low frequencies. 1
Inductors have high reactance at high frequencies 1
loudspeaker 2 operates at high frequencies. 1
- (a)
(b)(i)V1
(ii)
1
1
WhenV, V1
mA1
(c)(i)For optimal bias voltage, V = 0.6 V1
1
1
(ii)Voltage gain = 1
Peak voltage for a.c. output = V1
(iii)When the CRO is switched to the a.c. mode, a capacitor is built in the CRO, which can replace the function of C2. 1
8.(a)(i)
(b)(i)breaking stress = 1
= 1.98×108 Pa1
(ii)work done = 1
= 0.125 J1
(iii)1
= 1.41×1011 N m-21
9(a)J1
(b)When yellow light incidents to cathode, photoelectrons are ejected from cathode C towards anode A. 1
When V = 1V, even the most energetic photoelectron cannot reach A. Therefore, the reading does not increase further. 1
(c)Stopping potential is the minimum potential to stop the most energetic electron from reading the anode A. 1
(d)Even the light intensity is increased, the energy of each yellow light photon remains unchanged. 1
The maximum K.E. of photoelectron is also unchanged so that the stopping potential is the same. 1
(e)(i)
(ii)Work function = 1
= 1.99×10-19 J1
accept: (1.86 – 2.12)×10-19 J
(iii)parallel line : 1
greater fo: 1
10.(a)1
= 2.01×10191
(b)Decay constant is the probability of an unstable nucleus to decay per unit time.1
1
= 0.131 year –1 1
(c)(i)1
= 2.63×1018 year –11
(ii)1
= 6.89×1024 eV year-1
= 0.035 W1
(iii)1
= 2.19 mW1
(d)Less energetic particles are absorbed by the skin.1
(e)For the same mass, technetium has greater activity than cobalt.1
The source technetium can be disposed at a earlier time than the source cobalt.1
S.7 Physics Mock Exam (01-02) / Paper I / Suggested Answer / P.1