Question Library

Excess charges placed on a spherical conductor repel and move until they are evenly distributed.

No expanded working has been attached for this question yet. The verified answer is Option E.

No expanded working has been attached for this question yet. The verified answer is Option D.

No expanded working has been attached for this question yet. The verified answer is Option D.

a) Diagram - Correct shape in relation to h and t - h varies parabolically with t - correct shape in relation to h and t\(^{2 }\) - h varies linearly with t\(^2\)

The expected answer is: Let R represent the horizontal distance covered at time, t. h = ½ gt\(^2\) 20 = ½ x 10 x t\(^2\) t = 2 s R = ut = 15 x 2 = 30m

Mercury does not wet glass because (force of) cohesion/attraction of mercury molecules is greater than (force of) adhesion/attraction between glass and mercury molecules. Water wets glass because (force of) adhesion/attraction between glass and water molecules is greater than (force of) cohesion/attraction of water molecules.

(a) Cations – are positive ions that are attracted to the cathode (during electrolysis) (b) Diagram Correct diagram/sketch: labeling cathode, anode and electrolyte.

(a) If the same quantity of electricity is passed through different voltameters/electrolytes connected in series the masses of the substances liberated/deposited during electrolysis is (directly) proportional to their chemical equivalents. OR The mass of an element deposited/liberated during electrolysis is (directly) proportional to the chemical equivalent of the element. (b) Let e represent the electronic charge. e = Faraday’s constant Avogadro’s number = 9.6 x 10\(^4\) 6. 0. x 10\(^{23}\) = 1.60 x 10\(^{-19}\)C

(a) Tensile stress is the ratio of force to cross-sectional area of a wire/rod. It is expressed in Newton per metre squared (Nm\(^{-2}\)) (b) Young’s modulus is the ratio of tensile stress to tensile strain. It is expressed in Newton per metre squared. (Nm\(^{-2}\))

(a) Diffusion is the process by which substances mix (intimately) with one another due to the random motion of their molecules. (b) Applications of electrical conduction through gases include:. - In advertising industry/Neon signs - In lighting/fluorescent tubes - Identification of gases - Cathode ray oscilloscope/T.V. tubes

(a) Properties of cathode rays: Cathode rays are negatively charged. travel in straight line in field free space. are deflected by electric/magnetic field. possess(kinetic) energy. possess momentum. (b)(i) The intensity of cathode rays may be increased by raising the temperature of the cathode/increasing the current through the heater. (ii) The energy of cathode rays may be increased by raising the potential difference between the anode and the cathode/the anode potential.

(a) PROCEDURE Make at least 3 well-spaced pin holes round the edge of the cardboard. Clamp the pin horizontally and suspend the cardboard on it through one of the pin-holes such that the cardboard can swing freely Hang the simple pendulum on the same pin and let its string be very close to the cardboard. When the whole system is at rest (or in equilibrium) trace the plumbline on the cardboard. Repeat the procedure for each of the two other pin holes. CONCLUSION The point at which the (three) traced lines intersect is the centre of gravity of the cardboard. PRECAUTIONS - Repeat procedure - Pin rigidly and firmly held by retort stand and clamp - Allow the simple pendulum to rest before tracing the shadow of the plumbline on the cardboard. - The string to be close to the cardboard b) Diagram: Both axes correctly labelled Any correct shape of graph showing acceleration segment Acceleration = gradient of AB Total distance covered = area under the graph (c) Diagram - At least one axis labelled - correct shape of graph Let V\(_1\) = maximum velocity after 20 sec. V\(_2\) = maximum velocity after 30 sec. (i) Then \(\frac{V_1}{20}\) = 6 ∴ V\(_1\) = 120 ms\(^{-1}\) Also V\(\frac{V_2 - V_1}{10}\) = 4 \(\frac{V_2 - 120}{10}\) = 4 V\(_2\) = 160 ms\(^{-1}\) Maximum speed = V\(_2\) = 160ms\(^{-1}\) (ii) Total distance covered = Area of \Delta + Area of trapezium after 1st 30 seconds = ( ½ x 20 x 120) + ½ (120 + 160) x 10 = 1200 + 1400 = 2600m (iii) Average speed = \(\frac{\text{Total distance}}{\text{ Total time}}\) = \(\frac{ 2600}{30}\) = 86.67 ms\(^{-1}\)

(a) A clinical thermometer has small temperature range. The glass will crack/burst due to excessive pressure created by expansion of mercury. (b) Increase in pressure (i) increases the boiling point; (ii) decreases the melting point. (c) At the boiling point of pure water, the saturated vapour pressure (s.v.p) of the water is equal to the external atmospheric pressure. (d) Diagram Volume V is proportional to length Ɩ stated or implied (i) P\(_1\)V\(_1\) = P\(_2\)V\(_2\) implies P\(_1\)P\(_1\) = P\(_2\)P\(_2\) (76 + 20) 15 = 76 x L\(_2\) Ɩ\(_2\) = 96 x 15 76 Ɩ\(_2\) = 18.95 cm (ii) P\(_1\)L\(_1\) = P\(_3\) L\(_3\) = (76 + 20) 15 = (76 – 20) x Ɩ\(_3\) Ɩ\(_3\) = 96 x 15 56 Ɩ\(_3\) = 25.7l cm

(a) Differences between a sound wave and a radiowave Sound wave Radio wave is a mechanical wave is an electromagnetic wave is longitudinal is transverse has speed less than speed of light. has speed equal to that of light requires a material medium for propagation/cannot travel through vacuum. does not require a material medium for propagation/can travel through vacuum. (b) The vibrating tuning fork forces the table top to vibrate. The table top has a much larger area and is therefore in contact with a larger volume of air undergoing vibration. Hence, sound heard is amplified. (c) Conditions necessary for: (i) production of stationary wave - Two waves must be traveling in opposite directions. - Incident and reflected waves must have the same frequency/wavelength. - Incident and reflected waves must have equal amplitude. - There must be superimposition. - There must be a barrier (ii) formation of interference wave pattern - Two sources must be involved. - The two sources must be coherent/have a constant phase difference as well as the same frequency and amplitude. - The waves that are interfering must have the same amplitude - The distance between the sources must be of the order of the wavelengths of the waves. (iii) total internal reflection - The wave must be traveling from a denser medium to a less dense medium - The angle of incidence of the wave in the denser medium must be greater than the critical angle for the medium. (d)(i) Diagram Correct diagram (ii) \(\frac{ Sin (A + dm)}{2}\) n = Sin (A/2) Sin (60 + 41)/2 Sin (60/2) = 1.54