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Work done on a stretched cord = Average force x extension = \(\frac{1 \times 10 \times 0.012}{2}\) = 6.0 x 10\(^{-2}\)J

F = Ke (Hooke's law) K = F/e = 80/4 = 20 Nm-1

\(R^2 = 100^2 + 60^2\) 10000+3600 = 13600 R = \(\sqrt{13600}\) = 117km 60km & 100km = tan\theta = \(\frac{60}{100}\) \(tan^{-1}\) 0.6 = 31º west of the North 117km N31ºw

pressure in fluid is given by P = hpg. ∴ fluid pressure depends on height of liquid column, h, density of liquid p and acceleration of free fall g. it is therefore independent of type of container and constituents of the liquid.

Liquid boils when its saturated vapor pressure is equal to the (external) atmospheric pressure. I.e. Boiling point at 100^\circc

The energy supplied by the heater = heater gained by the water pt = Mc\(\Delta\)\theta 1000 x 300 = m x 4200(100 - 30) m = \(\frac{(1000 \times 300)}{4200 \times 70}\) = 1.02 kg

F ∝ \(\frac{M_1 M_2}{r^2}\) F = \(\frac{GM_1M_2}{r^2}\) where F is the force of attraction M\(_1\) and M\(_2\) are the masses of the two bodies, r is the distance between them, and G is the universal gravitational constant Therefore, G = \(\frac{Fr^2}{M_1M_2}\) Dimension for F = \(\frac{\text{ML}}{T.T}\) = MLT\(^{-2}\) The dimension for G = \(\frac{MLT^{-2}L^2}{M.M}\) = \(\frac{L^3T^{-2}}{M}\) = M\(^{-1}\)L\(^3\)T\(^{-2}\) In comparison with M\(^x\)L\(^y\)T\(^z\), the values for x, y and z = -1, 3, -2

The leaves collapse as the positive charges on the rod neutralize the negative charges on the electroscope.

The electric potential at a point in an electric field is defined as the amount of work done in moving a unit positive charge from infinity to that point against the action of the field. V = \(\frac{Q}{4 \pi∈r}\)

1/R = 1/R1 + 1/R2 = 1/3 + 1/6 = 3/6 ∴ R = 6/3 = 2 E = I(R + r) = 4(2 + 0) = 8v

V = \sqrt \({(v_l - v_c)}^2 + V^2R\) V =\sqrt \({(40 - 110)}^2 + 80^2\) V = \sqrt \({-70}^2 + 80^2\) =\sqrt 4900 + 6400 =\sqrt 11300 = 106.3v

Thermionic emission is ejection of electron from a metal surface as a result of heating.

Metals are good conductors due to the presence of free electrons.

When a pentavalent (5 outer electron)atom is added to a pure semiconductor, there is an extra electrons which does not take part in the covalent bonding resulting in an n-type semiconductor.

Canorous cells can be destroyed with a high penetrating radiation which is x - rays