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

(a)(i) Temperature is a number which expresses how hot or cold a body is on scale such as centigrade or kelvin. S.I. unit is kelvin (K). Temperature decides which direction heat will flow while, heat is a form of energy S.I. is Joules (J). (ii) Two physical properties used for measuring temperature are:- (1) Change in volume of liquid with temperature (2) Change in resistance. Others are: (3) Expansion of solids (4) Expansion of volume of gas. (b)(i) Determination of the upper - fixed point for a mercury-in-glass thermometer. To determine the upper fixed point, a hypsometer is used. The experiment is set up as shown above. The manometer is used to measure the pressure of the steam. If it is not 76cm Hg, an adjustment is made to the upper fixed point. When the mercury level is constant, a mark is made on its glass to fix the point. One precaution that must be observed in this experiment is that the thermometer must not touch the water, because its temperature is affected by dissolved impurities in the water. (ii) The constant - volume gas thermometer measures temperature more accurately than other thermometers because its glass expansion is negligible compared to the expansion of the gas. It is seldom used as everyday laboratory thermometer because it is not easily handled unlike the laboratory thermometer. (c) In the kinetic theory, molecules are in random motion. They all have different velocities. Near the surface, some liquid molecules with high velocities in an upward direction may have sufficient kinetic energy to break through the surface. Then they become molecules of vapour. The average kinetic energy of the liquid remaining is therefore reduced, and so its temperature is lowered.

(a)(i) Mode of Operation: In the X-ray tube a Low voltage high p.d is applied between the hot cathode and the anode. Electrons are emitted from the cathode and are accelerated to an extremely high speed. They are suddenly decelerated when they strike the anode causing the emission of high - energy radiation of short wavelength - X-ray. In this process the anode becomes very hot, and requires cooling fins on the outside of the tube. Energy Transformation: The electrons have kinetic energy which is partly changed to internal energy (potential) and finally changed to heat energy. (b) Hardness: Refers to X-rays with high penetrating power, short wavelength but high frequency. They are produced by increasing the p.d. between the cathode and anode. Such X-rays are called hard X-rays. Less penetrating or lower frequency ones are called soft X-rays. They are produced at lower p.d. Intensity: High intensity X-rays beam results from the increase of current through the filament which leads to increase in the number of electrons. (c)(i) Uses of X-rays: (1) Investigating the structure of crystals ; (2) X-ray examination of the body for broken bones; (3) As invincible bullets for the treatment of tumours ; (4) Examination of metals for defects and fractures. (ii) They may cause damage to living tissue and to cells. Precaution to be taken includes lead screening and regular health checks.

F = ma = 2.5 x 10-6 x 4 x 107 = 100N

Kinetic energy at O = P.E at P 1/2mV = mgh h = v/2g = 0.2m

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

D = v x t = 7 x 0.3 = 2.1m

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

E = \(\frac{\text{M.A}}{\text{V.R}}\) ; \(\frac{50}{100}\) = \(\frac{\text{M.A}}{2}\) M.A = 1; \(\frac{\text{L}}{\text{E}}\) = 1 E = L = 120N

Reading = mg + ma = m(g + a) = 55(10 + 2) = 660N = 66kg

couple moment = F x d = 4 x 0.4 = 1.6Nm

resolving F into its components \(F_x\) = Fcosϴ \(F_y\) = Fsinϴ Work done = Force x Distance = Fcosϴ \(\times\) x = Fxcosϴ

Water has a peculiar property. When temperature rises between 0 to 4^\circC water is not going to expand but it is going to contract. This special property is called anomalous. Therefore at 4^\circC volume of the water is minimum and the corresponding density is maximum.

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

F = Gm1m2/r2 = 7 x 10-11 x 106 x 103/1m = 7 x 10-2