2008/2009 UNN Physics Post-UTME

Which of the following is a derived unit?

A bat emits its sound at a speed of 1650s and receives the echoes 0.15s later. Calculate the distance of the bat from the reflector.

Two identical waves travelling in the same direction are super imposed. What should be the phase difference between the waves for maximum destructive interference to occur?

The odour of a leaking gas is perceived at a distance from the source. This is made possible by the process of

$$\begin{gathered} \mathrm{A} \mathrm{train} \mathrm{has} \mathrm{an} \mathrm{initial} \mathrm{velocity} \mathrm{of} 44\mathrm{m}/\mathrm{s} \mathrm{and} \mathrm{an} \\ \mathrm{acceleration} \mathrm{of}– 4\mathrm{m}/{\mathrm{s}}^2, \mathrm{its} \mathrm{velocity} \mathrm{after} 10\mathrm{s} \mathrm{is} \end{gathered}$$

A simple pendulum with a period of 2.os has its length doubled. Its new period is

$$\begin{gathered} \mathrm{An} \mathrm{object} \mathrm{is} \mathrm{projected} \mathrm{with} \mathrm{a} \mathrm{velocity} \mathrm{of} 100{\mathrm{ms}}^{–1} \\ \mathrm{from} \mathrm{the} \mathrm{ground} \mathrm{level} \mathrm{at} \mathrm{an} \mathrm{angle} \mathrm{to} \mathrm{the} \mathrm{vertical}. \\ \mathrm{Total} \mathrm{time} \mathrm{of} \mathrm{flight} \mathrm{or} \mathrm{the} \mathrm{projectile} \mathrm{is} 10\mathrm{s}, \mathrm{calculate} (\mathrm{g}=10{\mathrm{ms}}^{–1}) \end{gathered}$$

A gas has a volume of 546cm² at 0⁰ What is the volume of the gas at 100⁰C if its pressure remains constant?

In electrolysis experiment a cathode of mass 5g is found to weigh 5.o1g after a current of 5A flows for 50seconds. What is the electrochemical equivalent of the deposited substance?

A magnetic needle is suspended first at earths north magnetic pole and then at point on the magnetic equator? The respective angles between the needle and the horizontal are