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5×102 ms−1
4×101 ms−1
2×104 ms−1
3×103 ms−1
5×1012 s−1
4×1010 s−1
2×1014 s−1
3×1013 s−1
The frequency of a single ion set into oscillation is given as:
ω=√e2/MR3
ω=e2/MR3
ω=√MR3/e2
ω=MR3e2
8, out of which 2 are acoustic and 6 optical
9, out of which 3 are acoustic and 6 optical
12, out of which 3 are acoustic and 9 optical
12, out of which 2 are acoustic and 10 optical
ℏ2/γa2cos(ka)
ℏ2/2γa2cos(ka)
ℏ2/γa2sin(ka)
ℏ2/2γa2sin(ka)
E=E0−β−2γcoska
Where E0,β and γ are constants and k is the wave vector.
The density of states of electrons (including spin degeneracy) in the band is given by
a) Lπγasin(ka)
b) L2πγasin(ka)
c) L2πγacos(ka)
d) Lπγacos(ka)
2.
A) The distance 𝑺 moved by an object in time 𝒕 may be given by the expression 𝑺 = 𝟏/ 𝟐
𝒂𝒕2
Where 𝒂 is the acceleration of the object.
State two conditions for this expression to apply to the motion of an object.
B) A car travelling along a straight road at a speed 𝒗. A hazard suddenly appears in front of the car. In the time interval between the hazard appearing and the brakes on the car coming into operation, the car moves forward a distance of 29.3m. with the brakes applied, the front wheels of the car leave skid marks on the road that are 12.8m. It is estimated that, during the skid, the magnitude of the decoration of the car is 0.85𝑔, where 𝑔 is the acceleration of free fall.
Determine
(i) The speed 𝑣 of the car before the brakes are applied,
(ii) The time interval between the hazard appearing and the brakes being applied .
(iii) The legal speed limit on the road is 60kmph. Use both your answers in (B) to comment on the standard of the driving of the car.
1.
A ) Define pressure?
B) A cylinder is placed on a horizontal surface. The following measurements were made on the cylinder: mass = 5.09 ± 0.01kg diameter = 9.4 ± 0.1cm
(i) Calculate the pressure produced by the cylinder on the surface.
(ii) Calculate the actual uncertainty in the pressure.
(iii) State the pressure with its actual uncertainty.
(iv) Distinguish between a systematic and a random error. [10marks] 7.
4. A Stone is thrown with a horizontal velocity of 20m𝑠 −1 from the top of a cliff 15m high. Air resistance is negligible, for this stone:
(i) Calculate the time to fall 15m,
(ii) Calculate the magnitude of the resultant velocity after falling 15m,
(iii) Describe the difference between the displacement of the stone and the distance that it travels.
1). Two strings support a load of weight 7.5N, One string has a tension 𝑇1 and is at an angle 50° to the horizontal. The other string has a tension 𝑇2 and is at angle 40° to the horizontal. The object is in equilibrium. Determine the values of 𝑇1 and 𝑇2 by using a vector triangle or by resolving forces. [4marks]
2). A cylindrical disc has diameter 28mm and thickness 12mm. the material of the disc has density 6.8 × 103kgm−3 . Calculate, to two significant figures, the weight of the disc.
