Solutions to SQA examination

1993 Higher Grade Physics

Paper I Solutions

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1. D		11. E			21. B
2. B		12. B			22. A
3. C		13. C			23. E
4. D		14. E			24. A
5. A		15. E			25. A
6. D		16. C			26. C
7. B		17. A			27. C
8. E		18. B			28. D
9. A		19. E			29. B
10.D		20. C			30. D

31.a.	VHor = Vcosq
	VHor = 24.0cos60o
	VHor = 12m/s
	Note: the horizontal component of velocity is constant between P and X.

   b.   SHor = VHort
	SHor = 12x26
	SHor = 312m

	Fres = (9x104-4x104)3
	Fres = 5x104x3
	Fres = 15x104N	 (to the left)

33.a.	RP/RQ = RR/RS
	When this is true the reading on the voltmeter is 0V.

   b. 	The p.d. across the battery does not affect the above ratio of the 
	resistors. The bridge is therefore still balanced, and the voltmeter
	reading will not change from 0V.

34.a.	VRMS = Vpeak/SQRT2
	VRMS = 10/1.414
	VRMS = 7.07V

   b. 	f = 1/T

	T = 8x0.2ms = 1.6ms
	T = 1.6x10-3

	f = 1/1.6x10-3
	f = 625Hz

35.a.	The pupil assumes that there is 100% efficiency in the process
	converting the energy stored in the capacitor into heat energy.
	There is also the assumption that all the heat energy is absorbed
	by the oil.

   b. 	The energy stored in the capacitor can be calculated using: E = CV2/2

	E = 5x10-6x102/2
	E = 2.5x10-4J

	This amount of energy would not produce a measurable change in the 
	temperature of the oil.

36.	For the first minimum:
	Path difference = 1/2l
	AB-AP = 1/2l
	43-41 = 1/2l
 	2 = 1/2l
	l = 4cm

37.a. 	Alpha radiation.

   b.	The fact that most of the radiation passes straight through indicates
	that most of the atom must be empty space. However, the fact that some
	"bounces back" provides evidence that the alpha particle occasionally
	collides with a massive body. It is therefore reasonable to conclude
	that atoms are mainly empty space with a large mass concentrated at 
	the centre. 


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