Download 2003 Q5 - Loreto Balbriggan

State Examinations Commission – Physics Higher Level, 2003.
Question 5.
Answer any eight of the following parts (a), (b), (c), etc.
(a) State Hooke’s law.
(b) What is the relationship between the acceleration due to gravity g and the distance from the centre
of the earth? (
(c) The diagram shows forces of 5 N applied to a water tap. Calculate the
moment of the couple (torque) on the tap. (7)
(d) Which wave phenomenon can be used to distinguish between transverse waves and longitudinal
waves?
(e) Sound intensity level can be measured in dB or dB(A). What is the difference between the two
scales?
(f) Calculate the critical angle for diamond. The refractive index of diamond is 2.4.
(g) What is the purpose of a miniature circuit breaker (MCB) in an electric circuit?
(h) What is the photoelectric effect?
(i) What is meant by nuclear fusion?
(j) Give one contribution made to Physics by either Paul Dirac or Nicholas Callan.
_________________________________________
(a) State Hooke’s law.
The extension of an elastic material is proportional to the force causing it
(b) What is the relationship between the acceleration due to gravity g and the distance from the centre
of the earth?
g∝
1
or
g=
GM
where d = distance from center of earth, G = Universal Gravitational
d
d2
Constant and M = mass of Earth
2
(c) The diagram shows forces of 5 N applied to a water tap. Calculate the
moment of the couple (torque) on the tap. (7)
Moment of couple = F x d = 5 x 6 = 30 Ncm
(d) Which wave phenomenon can be used to distinguish between transverse waves and longitudinal
waves?
Polarization
(e) Sound intensity level can be measured in dB or dB(A). What is the difference between the two
scales?
The dB(A) scale is adapted to take into account the frequency response of the ear.. It responds more to
frequencies that are likely to damage human hearing, between 2000 and 4000 Hz.
Chris Garvey 2003
(f) Calculate the critical angle for diamond. The refractive index of diamond is 2.4.
1
sinC
1
2.4 =
sinC
1
sinC =
= 0.417
2.4
C = 24.6o
n=
(g) What is the purpose of a miniature circuit breaker (MCB) in an electric circuit?
To break the circuit if too large a current flows
(h) What is the photoelectric effect?
It is the emission of electrons from the surface of a metal when em radiation of sufficient energy is
incident upon it.
(i) What is meant by nuclear fusion?
It is the combining of two light nuclei to produce a heavier one, accompanied by the emission of a
large quantity of energy
(j) Give one contribution made to Physics by either Paul Dirac or Nicholas Callan.
Dirac predicted anti-matters existence.
Chris Garvey 2003