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Sound waves are mechanical waves, which means they require a medium to travel through. They can travel through all three states of matter: gases (like air), liquids, and solids.

f = 250 Hz; \lambda = 1.3 m; t = 1 s; d = ? v = f\lambda = 250 \times 1.3 = 325 ms\(^{-1}\) v = \(\frac{2d}{\text{t}}\) ∴ d = \(\frac{v \times t}{2}\) = \(\frac{(325 \times 1)}{2}\) = 162.5 m

Quality (overtones) is a characteristic note of a musical instrument that distinguishes it from another note of the same pitch and loudness produced by another instrument.

\lambda = 1 m; v = 200 ms\(^{-1}\); f = ?; f = \(\frac{\text{v}{ \lambda}\) = \(\frac{200}{1}\) = 200 Hz

Short-sightedness (myopia) means distant objects focus in front of the retina, with the far point at 95 cm. A diverging lens (concave) corrects this by creating a virtual image of distant objects (u = \infty) at the far point (v = -95 cm). Using the lens formula: 1/f = 1/v - 1/u = -1/95 - 0, so f = -95 cm (diverging lens with focal length 95 cm).

B. Ciliary muscle. The ciliary muscles control the shape of the lens, allowing the eye to focus on objects at different distances by changing the focal length of the lens.

The tension \( T \) in a string is defined as the force acting along the string. The dimensional formula for force is given by: \([T] = [F] = [M^1 L^1 T^{-2}]\) Thus, the dimensional symbol of tension in a string is: \([T] = [M L T^{-2}]\)

From Faraday's first law, the mass deposited \( m = Z Q \), where \( Z \) is the electrochemical equivalent and \( Q \) is the charge passed. Since the same charge \( Q \) passes through both voltmeters: \(Q = \frac{m_{\mathrm{Cu}}}{Z_{\mathrm{Cu}}} = \frac{m_{\mathrm{Ag}}}{Z_{\mathrm{Ag}}} \) Rearranging for \( Z_{\mathrm{Ag}} \): \(Z_{\mathrm{Ag}} = \frac{m_{\mathrm{Ag}} \cdot Z_{\mathrm{Cu}}}{m_{\mathrm{Cu}}} \) But: \( m_{\mathrm{Cu}} = 0.2 \, \mathrm{g} \), \( m_{\mathrm{Ag}} = 1.2 \, \mathrm{g} \), \( Z_{\mathrm{Cu}} = 0.00028 \, \mathrm{g \, C^{-1}} \) \(Z_{\mathrm{Ag}} = \frac{1.2 \times 0.00028}{0.2} = \frac{0.000336}{0.2} = 0.00168 \, \mathrm{g \, C^{-1}} \)

Answer: A. Red (Visible spectrum: red ~700 nm, longest; violet ~400 nm, shortest.)

Lens power P = 1/f, where f is focal length in meters; unit is diopter.

The two displacements are 6.0 m East and 10.0 m at N30ºE. The angle between East and N30ºE is 60^\circ. Using the cosine rule: R\(^2\) = 6\(^2\) +10\(^2\) +2(6)(10)cos60º R\(^2\) = 36 + 100 +120 (0.5) = 196 R = \(\sqrt{196}\) = 14.0m

Answer: D. 10cm³ (Volume ice = \(\frac{90}{0.9}\) = 100 cm\(^3\); volume water = \(\frac{90}{1}\) = 90 cm\(^3\); change = 10 cm\(^3\) decrease.)

Answer: D. thermodynamic (Pressure law P ∝ T requires an absolute scale like Kelvin (thermodynamic) for a line through the origin at T= 0, P= 0. Rankine is also absolute but less common in this context.)

D. Rate of change of momentum imparted to the walls per second per unit area. (Pressure = force/area = (rate of momentum change)/area from molecular collisions.)

Answer: D. It is longitudinal (String waves are transverse; perpendicular to propagation.