ai. Why are parabolic mirrors suitable for use in the headlamps of vehicles?

ii.  Draw a ray diagram to illustrate the answer in 10(a)(i).

bi. State two applications of echoes.

                      

ii. An observer standing at a point, P, on the same horizontal ground as the foot, H, of a tower, shouts, and 1.20 s later, he hears the echo. He then moved to another point, Q, 40 m from P, and shouted again but the echo was heard after 1.45 s. Calculate the:
I. distance between P and H;
II. speed of sound in air.

ci. Define the term absolute refractive index of a medium.

ii. A piece of coin falls accidentally into a tank containing two immiscible liquids A and B as illustrated in Fig. 10.0 above.

   

Calculate the displacement of the coin when viewed vertically from above.
[refractive index of A = 1.3, refractive index of B = 1.4]