An electron of mass, m, and charge, e moves through the electric field of potential difference V\(_o\) with a speed, v. Show that de Broglie wavelength associated with the electron is given as \(\lambda\) = \(\frac{\text{h}}{\sqrt{2meV_o}}\), where h is the Plank's constant.

The fractional change in length produced in an elastic material of spring constant 680Nm\(^{-1}\) when a force of 306N is applied to stretch it is 1.5. Calculate the original length of the material.

                                                   PART2

(a) State the effect of increasing temperature on the viscosity of a: (i) liquid, (ii) gas

(b) State two factors that determine the magnitude of a moment of a force

(c) A uniform stick AB of length, L, and mass, m, is balanced horizontally on a knife edge 10.0cm from A when an object of 400 g is suspended at A. When the knife edge is moved 5 cm further, the object has to be moved to a point 9.00 cm from A for the stick to balance.

(i) Represent the balance system with a suitable diagram

(ii) Determine the: I. mass, m of the stick; II. length, L.

(d) Explain in terms of air molecules why pressure at the top of a high mountain is less than at sea level.

(e) Mercury of density 13.6 x 10\(^3\)kgm\(^{-3}\) is poured in a container of uniform cross-sectional area 40cm \(^2\) to a height of 20 cm. The total pressure exerted on the base of the container is 1.42 x 10\(^5\)P. Calculate the: (i)  mass of the mercury in the container and (ii) pressure exerted at the surface of the mercury. [g = 10ms\(^{-2}\)

(a)(i) What is a thermometric liquid?

(ii) State the reason for the following design features of a clinical thermometer. I. Narrow bore: II. Thin wall of the bulb 

(b) Distinguish between heat and temperature of an object in terms of the energy of a particle

(c) Explain why evaporation leads to cooling

(d) A kettle rated 2000W, contains water at 20ºC. The kettle is switched on and after two minutes, the water starts boiling. After another six minutes, 45% of the water in the kettle boils away. (i) Determine the specific latent heat of the vaporization of the water (ii) State one assumption made in your calculation 9d(i) above

(a) State the condition for light ray incident on a concave mirror to reflect through the principal focus of the mirror.

(b) Explain spherical aberration as a defect of curved mirrors

(c) The diagram above illustrates an image formed when an object is placed in front of a particular lens. Redraw the diagram and indicate the center of curvature, C, principal focus, F, and the principal axis. ( SEE THE DIAGRAM ABOVE)

(d) What is meant by accommodation in connection to the human?

(e) State quantitatively, the (i) values of the near and far point of a normal eye. (ii) Use the answer in 10c(i) to determine the change in optical power of the normal human eye when reading a book and viewing the sky.[lens-to-retina distance = 2.5 cm].