(a) State the three characteristics of sound and the factor on which each of them depends.

(b) Explain resonance as applied to sound.

(c) What role does echo play in the construction of a concert hall?

(d) The surface of an ear drum (assumed circular) has a radius 2.1 mm. It resonates with an amplitude of 0.8 x 10\(^{-7}\) in as a result of impulses received from an external body vibrating at 2400 Hz. If the resulting pressure change on the ear drum is 3.6 x 10\(^{-5}\) NM\(^{-2}\), calculate the:

(i) period of oscillation;

(ii) velocity;

(iii) acceleration;

(iv) force. [\(\pi\) = 3.14 ].

(a) Define electromotive force.

(b) State:

(i) the principle of operation of a potentiometer,

(ii) two advantages that a potentiometer has over a voltmeter in measuring potential difference.

(c)(i) Sketch and label a diagram of a gold-leaf electroscope.

(ii) Give one use of a gold-leaf electroscope.

(d)(i) Explain the action of a magnetic relay.

(ii) List two factors which determine the magnitude of an induced emf in a coil.

(iii) A current of 5 A passes through a straight wire in a uniform magnetic field of flux density 2.0 x10\(^{-3}\) T. Calculate the force per unit length exerted on the wire when it is inclined at 30° to the field.

 (a) Write Einstein's photoelectric equation and identh: each component of the equation.

(b) For a photocell, star; one factor each that is responsible fo: the:

(i) emission (ii) rate of emission;

(iii) energy of photoelectrons.

(c)(i) Two nuclear equations are given below:

\(^{222}_{p}RN\) \(\to\) \(^{218}_{84}PO + ^q_2He\)...................A

\(^{214}_{83}RN\) \(\to\) \(^{214}_{84}PO + ^m_nX\)...................B

Determine the values of: (\(\alpha\)) p and q in equation A; (\(\beta\)) in and n in equation B and identify X.

(ii) Give a reason why it is important to dispose o radioactive waste safely.

(d)(i) A certain atom emits ultra violet photon of wavelength 2.4 x10\(^{-7}\)m. Calculate the energy of the photon:

----------------- - 6.0 x 10\(^{-19}\)J

---------------- - 8.2 x 10\(^{-19}\)J

---------------- - 8.8 x 10\(^{-19}\)J

---------------- - 16.7 x 10\(^{-19}\)J

(ii) The figure above illustrates the energy levels o the atom. Copy the figure in your answer booklet anc indicate on it, the energy level transitions which cause the emission of the photon in (d)(i) above. [h= 6.6 x 10\(^{-34}\) Js; c = 3.0 x 108 ms\(^{-1}\)].

A projectile is released with a speed u at an angle \(\theta\) to the horizontal. With the aid of a diagram, show that the time of flight is equal to \(\frac{2uSin\theta}{g}\), where g is the acceleration of free fall.

The horizontal component of the initial speed of a particle projected at 30° to the horizontal is 50 ms\(^{-1}\). If the acceleration cf free fall due to gravity is 10ms\(^{-2}\), determine its: (a) initial speed; (b) speed at maximum height reached.