2008 - JAMB Physics Past Questions and Answers - page 5
41
A
moving Q nearer to O
B
moving P nearer to O
C
addding a weight Q to Q
D
moving P further away from O
correct option: b
If 2P is added P, the beam will bend at R side. So to keep it in equilibrium. P should be moved nearer to 0
Users' Answers & Comments42
A
275N
B
325N
C
375N
D
573N
correct option: c
VR = No. of pulleys = 4
Efficiency = M.A/V.R x 100% = load
Effort x 100%_V.R
∴80 = 1200 x 100 x 1100__Effort4
∴ Effort = 1200 x 100 = 375N_80 x 4
Users' Answers & CommentsEfficiency = M.A/V.R x 100% = load
Effort x 100%_V.R
∴80 = 1200 x 100 x 1100__Effort4
∴ Effort = 1200 x 100 = 375N_80 x 4
43
A
melting region
B
boiling region
C
sublimation region
D
evaporating process
44
A
parallel to OX
B
parallel to OY
C
60o to OX
D
60v to OY
correct option: b
Particles of the transmitting medium in transverse wave oscillate in a direction perpendicular to the propagation of the wave
Users' Answers & Comments45
If a convex lens of focal length 12cm is used to produce a real image four times the size of the object, how far from the lens must the object be placed?
A
10 cm
B
15 cm
C
20 cm
D
25 cm
correct option: b
Magnifications = V/U = 4
∴ V = 4U
1/V + 1/U = 1/f
1/4u + 1/U = 1/12
5/4U = 1/12
4U = 12 x 5 = 60
∴ U = 15 cm
Users' Answers & Comments∴ V = 4U
1/V + 1/U = 1/f
1/4u + 1/U = 1/12
5/4U = 1/12
4U = 12 x 5 = 60
∴ U = 15 cm
46
A
6 Ω
B
12 Ω
C
18 Ω
D
24 Ω
correct option: d
The resistors are in series
∴ Reff = R1 + R2 + .....
= 4 + 4 + 4 + 4 + 4 + 4 = 24 Ω
Users' Answers & Comments∴ Reff = R1 + R2 + .....
= 4 + 4 + 4 + 4 + 4 + 4 = 24 Ω
47
A
0.35mH
B
3.50mH
C
2.90mH
D
35.0mH
48
If electron are accelerated from rest through a potential difference of 10kv, what is the wavelength of the associated electron
[m = 9.1 x 10-31kg, e = 1.6 x 10-19C, h = 6.6 x 10-34js]
[m = 9.1 x 10-31kg, e = 1.6 x 10-19C, h = 6.6 x 10-34js]
A
1.22 x 10-11m
B
3.87 x 10-10m
C
2.27 x 1011m
D
2.27 x 1014m
correct option: a
| λ = | __h |
| √(2evm) |
| = | ____6.6 x 10-34 |
| √(2 x 1.6x10-19 x 10000 x 9.1x10-34) |
1.223 x 10-11m
49
| 14 | N + | 4 | He → | 17 | O + X |
| 7 | 2 | 8 |
In the equation above, the particles X is
A
a proton
B
a neutron
C
an α - particle
D
a β - particle
correct option: a
for the conversion of mass 14 + 4 = 17 + x
∴ X = 18 - 17 = 1
for conservation pf charge:7 + 2 = 8 + y
y = 9 - 8 = 1
Thus, the element is 11X which is equal to hydrogen nucleus ( proton)
Users' Answers & Comments∴ X = 18 - 17 = 1
for conservation pf charge:7 + 2 = 8 + y
y = 9 - 8 = 1
Thus, the element is 11X which is equal to hydrogen nucleus ( proton)
50
Find the median of 4, 1, 4, 1, 0, 4, 4, 2 and 0
A
o
B
1
C
2
D
4