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Force required to move the object forward = Fcos 60 = 300 x 0.5 = 150N Frictional Force = 100N Total force acting on the object = 150 - 100 = 50N Work Done = Total force x distance = 50 x 4 = 200J.

Diagram above shows a Parallel circuit If one of the parallel path is broken, current will continue to flow in other parts. Voltage is the same across each component of the parallel circuit. The brightness of a light bulb is given by its power. P = I\(^2\)R, and so brightness depends on current and resistance. Hence; the brightness of Y will not be affected except for a variation in resistance property.

(a) This is the force of attraction of the Earth on a mass It is a vector quantity and is measured in ms\(^{-2}\) It pulls the acceleration when a body is in vacuum or without resistance. OR/F = g (all symbols explained) where F = force of gravity, M = mass of the object (b) — (Shape of the earth). The earth is not a perfect sphere (1) or the shape of the earth is elliptical - Rotation of the Earth about its polar axis. (c)(i) Let H = height of tower and h = vertical difference covered by the stone from the point of projection. (i) V\(_2\) = (Usin\(\theta\))\(^2\) - 2gh \(\theta\) = 100 x 100 x (\(\frac{1}{2}\))\(^2\) - 20h h = \(\frac{2500}{20}\) = 125m height above the ground (i) S = H + 125 S = 100 + 125 S = 225m (ii) V = U sin \(\theta\) – gt 0 = 100 sin 30^\circ – 10t t = \(\frac{100 \times 0.5}{10}\) t = 5s (iii) Using S = ut + 1/2 gt\(^2\) 225 = 0 + 1/2 x 10t\(^2\) t = \(\sqrt{45}\) = 6.71 Time of flight, T= 5 + 6. T = 11.71s (iv) Range R = UTcos\(\theta\) Or S = ut – 1/2 gt\(^2\) g = 0 =100 x 0.8660 x 11.71 = 1014.08 (C14) Range \(\frac{U^2 sin20}{ g}\) = 1013.22m

(a) Whenever there is a change in the magnetic flux linked with a circuit, an electromotive force is induced, (1\(\frac{1}{2}\)) the strength of which is proportional to the rate of change of the flux linked with the circuit (1\(\frac{1}{2}\)). E \(\alpha\) \(\frac{d \theta}{dt} or E = \frac{Nd \theta}{dt}\) Where E = induced e.m.f. \(\theta\) = magnetic flux. (b) Workability: All except key and capacitor. When the platinum contacts touch ar,d the key k is closed, current passes through the primary coil and the core is magnetised. The soft iron armature is then attracted so the, the platinum contacts separate and the circuit is broken. When this happens, the core loses its magnetism and the armature is pulled back by the spring so that contact is re-established. As the contact is repeatedly made and broken in the primary circuit, changes of magnetic flux take place and induces an e.m.f. in the secondary coil. Because of the much larger number of turns in the secondary compared with the primary, a very high e.m.f is induced in the secondary coil which is sufficient to cause a spark to jump across the spark gap. (c) The core of the coil is made of bundle of soft-iron wires OR that are of the coil is laminated. Or use of particle of iron dust. Or lamination of iron sheet or iron core not metallic sheet (d) – To control sparking at the platinum contacts (which otherwise wears off the contact points) -- It promotes a rapid decay of the magnetic flux at the break of the primary circuit and this helps to increase the secondary e.m.f. (e) It is used in the – coil – ignition system of motor cars – inveitigation of high voltages – study of electric discharge through gases – operation of x-ray tubes – merse radio transmitter.

(a) Surface tension is the property of a liquid which makes its surface behave as though covered with an elastic sink. Or it is the tangential force on the surface of a liquid. Surface tension is force per unit length on the surface of a liquid Consider two molecules A and B as shown above. The molecule A will be attracted uniformly in all directions trot pulled in any one particular. direction. On the other hand, B is attracted more by molecules within the body of the liquid and it therefore experiences a resultant inward force at right angles to the surface. There will therefore be a tendency for the surface of the liquid to contact and have as little an area as possible. The surface is thus in a tension. Diagram or description link NB: Water and needle shown but not labelled A beaker is filled to the brim with water as shown above. A dry needle is placed on a small piece of filter paper, which is then gently placed on the water surface. It would be observed that the filter paper sinks to the bottom of the beaker while the needle is left floating. The surface thereby acts like an elastic skin covering the liquid which is able to support the weight of the needle (c) – When water is allowed to drip slowly from a water tap, the shape of each small drop is spherical. - When mercury spills on a glass sheet, it forms spherical droplets. - Soap bubbles are spherical in shape. - Insects (water - skaker) area able to walk across a water surface etc. - Toy duck on liquid - A flowing or floating needle on water. (d) The adhesion of water molecules to glass molecules is stronger than the cohesion between water molecules. Hence, when water spills on a clean glass surface it spreads and wets the glass. On the other hand, the cohesion between mercury molecules is greater than the adhesion between mercury and glass molecules. Therefore when mercury spills on glass it forms small spherical droplets on larger flattened drops (e) By adding - detergent/soap - alcohol - oil - By heating the liquid/increasing the temperature of the liquid - adding camphor.

a) The boiling pointer of a liquid is the temperature at which its s.v.p. is equal to the external atmospheric pressure OR The temperature at which a (pure) liquid boils when the atmospheric pressure on it is 760 mm Hg. OR The temperature at which the liquid changes from the liquid to the gaseous state without change in temperature when the atmospheric pressure is normal (760mm Hg). Method: Some mercury is introduced into J - tube and the entrapped air removed. Some liquid is introduced into the shorter length of the J - tube above the mercury. The beaker and its contents are heated and the water stirred continuously. At a stage when the levels of mercury in the two limbs of the J-tube are the same the temperature is read. At this temperature the s.v.p of the liquid is equal to the atmospheric pressure, and this temperature is the boiling point of the liquid. The process is repeated with the beaker and its contents cooling. The temperature at which the levels of mercury in the two limbs are equal is read and the mean of the two taken. (c) Pressure on the liquid, impurities in the liquid. (d) The extra heat supplied during boiling is used in breaking the intermolecular attractions and in mabling the steam expand or enabling the molecules move further apart against the atmospheric pressure. Hence, there is no change in temperature during the change of state.

\(\frac{V_{1}}{T_{1}}\) = \(\frac{V_{2}}{T_{2}}\) x \(\frac{V_{1}}{27+273}\) = \(\frac{3V_{1}}{T_{2}}\) , \(T_{2}\)= 900K; T=627°C

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

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 A.

100W X 10h = 1000Wh = 1KWh thus cost is 2k

\(\lambda = \frac{v}{f} = \frac{400}{2000} = 0.2\)m

\(v^2 = u^2+2as=0^2 + 2\times 10\times 45 \Rightarrow v^2 = 900m^2s^{-2} \Rightarrow \\ v = \sqrt{900m^2s^{-2}} \Rightarrow v = 30ms^{-1}\)

\(V^2= U^2+2as\) =\(0+ 2\times 2ms^{-2}\times 9 =36ms^{-1}\) thus V=\(\sqrt{36m^2s^{-2}}\) = \(6ms^{-1}\)

\(P_1V_1=P_2V_2, V_2= \frac{72\times500}{76}cm^3\)