PHYSICS TESTLET IV

ST. MARTIN’S GIRLS SCHOOL, KIBAGARE
P.O.BOX 14960-00800
FORM 4 PHYSICS ASSIGNEMENT IV SATURDAY 12TH SEPTEMBER 2009
NAME_____________________________________________________________
1. What do you understand by the term radioactive decay?
2. What are isotopes?
3. Distinguish between nuclear fusion and fission.
4. A manager of a canning company has at his disposal sources emitting alpha beta and gamma radiations to use in determining whether or not a tin can is completely filled with pineapples. Which one would you advice him to use and why?
5. The table below shows the results of an experiment to determine the half-life of a radioactive source. By plotting a graph of counts per second against time in minutes, determine the half life of the source
6. Study the figure below( not drawn to scale) and answer questions that follow



a) Determine the frequency of the wave 3mks
b) On the same diagram, draw a wave, which has the same frequency and wavelength but has double amplitude and is 90o out of phase. 3mk
7. The figure below is a wiring system for three identical lamps A,B and C. A and B are each marked 240V, 100w
a) Identify component E.
b) State one property component E must have.
c) When the circuit is closed, all three lamps work and the current through E is 1.45A. Calculate i) the Power of lamp C
ii) Resistance of the filament of lamp A
d) An electrician checked the mains supply to the lamps using a test meter connected to the cathode ray oscilloscope. He found that the maximum p.d. was 250V at a frequency of 50HZ. On the grid below draw the trace the electrician obtained for a duration of 0.08seconds. ( Y-gain is set at 125V/div 4mks
e) State two advantages of using a cathode ray oscilloscope as a voltmeter. 2mks