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A black solution is a better radiator of heat and allow a better absorber of heat.

Thermometer is used to measure temperature Hydrometer is used to measure relative density of liquid. Spring balance is used to measure the weight of an object Beaker is used to measure or take volume of a liquid

Seven 40W lamps = 7 \times 40 = 280W Five 80W lamps = 5 \times 80 = 400W Total power = 280W + 400W = 680W = \(\frac{680KW}{1000}\) = 0.68KW The kilowatt hour = 0.68 KW \times 12 hrs = 8.16 KWh Cost is N 7 per KWh So the cost of running them = 8.16KWh \times N 7/KWh = 57.12

u = , H = 20, g = 10 From equation of motion under gravity H = ut ± \(\frac{1}{2}\)gt2, It is falling so g is +ve H = 0 + \(\frac{1}{2}\)gt2 H = \(\frac{1}{2}\)gt2 2H = gt2 \(\frac{2H}{g}\) = t2 t = \(\frac{\sqrt{2H}}{g}\) = \(\frac{\sqrt {2 \times 20}}{10}\) = √4 = 2s

Consider an inclined plane shown below, as the effort moves along OB, the load moves is lifted up through a vertical height AB V.R = \(\frac{\text{distance moved by effort}}{\text{distance moved by load}}\) = \(\frac{OB}{AB}\) But Sinθ = \(\frac{opp}{hyp}\) = \(\frac{AB}{OB}\) therefore; = \(\frac{OB}{AB}\) = \(\frac{1}{\sin \theta}\)

Using boyle's law P1V1 = P2V2 V2 = \(\frac{P_1 V_1}{200}\) = \(\frac{400 \times 10}{200}\) = 20cm3

Impulse = Force \(\times\) time Force has the dimension \(\frac{ML}{T^{2}}\), hence Impulse= \(\frac{ML}{T^{2}} \times T = \frac{ML}{T}\)

Given that \(u = 0ms^{-1}, a = 2ms^{-2}, s = 9m\) We can use the equation, \(v^{2}=u^{2} +2as\) so that we have, \(v^{2} = 0^{2} + 2\times 2\times 9\) \(v^{2} = 36; v= 6.0ms^{-1}\) Note; u = Initial velocity v = final velocity a = acceleration s = distance covered

The body while coming down is acted upon by acceleration due to gravity, hence, the vertical force is constant. Also, at maximum height, the vertical velocity is 0 and then increases as the body comes downward.

Resolving 100N into horizontal and vertical 100 sin45 = 0.7071 * 100 = 70.71 100cos45 = 70.71 Vertical forces = 100 - 70.71 → 29.29 Horizontal force = 70.71 + 60 → 130.71 Resultant of vertical and horizontal forces using pythagoras thoerem Resultant force (F) = m * a a = F/m → 133.9/10 a = 13.4

Upthrust = weight of liquid displaced = mass of liquid displaced \(\times\) acceleration due to gravity = \(\frac{200}{1000} \times 10\) = 2N

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

Convert velocity from \(kmh^{-1}\) to \(ms^{-1}\), by multiplying \(\frac{1000}{3600}\), \(72 \times \frac{1000}{3600}\) = \(20ms^{-1}\) Therefore, distance covered in 0.4s = \(20 \times 0.4 = 8m\)

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

The spring constant = the measure of stiffness = 2000\(Nm^{-1}\) Energy stored in a spring = Work done to stretch it through a distance = change in potential energy = \(\frac{kx^{2}}{2}\) = \(\frac{2000 \times (0.04)^{2}}{2}\) (converting 4cm to metres) = \(\frac{3.2}{2} = 1.60J\)