2009 - JAMB Physics Past Questions and Answers - page 2
When a pentavalent (5 outer electron)atom is added to a pure semiconductor, there is an extra electrons which does not take part in the covalent bonding resulting in an n-type semiconductor.
Users' Answers & Comments| F ∝ | M1M2 |
| __r2 |
| => F = | GM1M2 |
| __r2 |
where F is the force of attraction
M1 and M2 are masses of the two bodies, r is the distance between them, and G is the universal gravitational constant
| ∴ G = | _Fr2 |
| M1M2 |
| ∴ dimension for force, F = | ML | = MLT-2 |
| T.T |
| The dimension for G = | MLT-2L2 | = | L3T-2 |
| _MM | _M |
= M-1L3T-2
In comparison with MxLyTz, the values for x, y and z = -1, 3, -2
Users' Answers & CommentsR2 = 1002 + 602
10000 + 3600 = 13600
R = √13600 = 117km
60kml & = tan = 60/100
tan-1 0.6
= 31o west of the North
117km N31ow
Users' Answers & CommentsFrom S = ut + 1/2 at2
S = 1/2 ut2, since U = 0
Let S5 = distance in 5 seconds
= 1/2 x 4 x 52 = 2 x 25 = 50m
S4 = distance covered in 4 seconds
= 1/2 x 4 x 42 = 2 x 16 = 32m
Distance covered in the fifth second
S5 - S4 = 50m - 32m = 18m
Users' Answers & CommentsSum of momentum before collision
M1 U1 + M2M2
12 x 4.2 + 18 x 0
12 x 4.2
= 50.4
Sum of momentum after collision
(m1 + m2)v
= (12 + 18)v
= 30v
V = 50.4/30
= 1.7ms-1
Users' Answers & CommentsAt vt = terminal velocity
= zero acceleration
= uniform velocity
Users' Answers & Comments[R = 8.313 J mol-1K-1]
PV = nRT
| ∴ P = | nRT | = | 2 x 8.313 x 300 |
| _V | ___10-2 |
= 4.987 x 105 Nm-2
Users' Answers & Comments
Diffraction is spreading of wave after passing through a slit
Users' Answers & Comments
[c = 3 x 108 ms-1]