1993 - JAMB Physics Past Questions and Answers - page 1
1
Which of the following quantities has the same unit as the watt?
A
Force x time
B
Force x distance
C
Force x acceleration
D
Force x velocity
correct option: d
Users' Answers & Comments2
The external and internal diameter of a tube are measured as (32 ± 2)mm and (21 ± 1)mm respectively. Determine the percentage error in the thickness of the tube.
A
27%
B
14%
C
9%
D
3%
correct option: c
Actual thickness = 34 - 22 = 12
error thickness = 30 - 20 = 10
error = 12 - 10 = 2mm that is, (11 ± 1)mm
%error = \(\frac{1}{11}\) x \(\frac{100}{1}\)
= 9%
Users' Answers & Commentserror thickness = 30 - 20 = 10
error = 12 - 10 = 2mm that is, (11 ± 1)mm
%error = \(\frac{1}{11}\) x \(\frac{100}{1}\)
= 9%
3
Two forces of magnitudes 7N and 3N act at right angles to each other. The angle \(\theta\) between the resultant and the 7N force is given by
A
cos\(\theta\) = \(\frac{3}{7}\)
B
sin\(\theta\) = \(\frac{3}{7}\)
C
tan\(\theta\) = \(\frac{3}{7}\)
D
cot\(\theta\) = \(\frac{3}{7}\)
4
A rocket burns fuel at the rate of 10kgs-1 and ejects it with velocity of 5 x 103ms-1. The thrust exerted by the gas on the rock is
A
2.5 x 107N
B
5.0 x 104N
C
5.0 x 102N
D
2.0 x 10-3N
correct option: b
Thrust = \(\frac{\text{mass x velocity}}{time}\)
= 10 x 5 x 103
= 5.0 x 104N
Users' Answers & Comments= 10 x 5 x 103
= 5.0 x 104N
5
The force experienced by an object of mass 60.0kg in the moon's gravitational field is 1.002 x 102N. What is the intensity of the gravitational field?
A
0.60Nkg-1
B
1.67Nkg-1
C
6.12 x 102Nkg-1
D
9.81ms-2
6
Which of the following correctly describes the energy changes in the generation of light by a hydroelectric power station?
A
Electrical \(\to\) mechanical \(\to\) potential
B
potential \(\to\)mechanical \(\to\)electrical \(\to\) light
C
mechanical \(\to\) sound \(\to\) electrical \(\to\) light
D
kinetic \(\to\) mechanical \(\to\) electrical \(\to\)light
correct option: b
Users' Answers & Comments7
A plane inclined at angle \(\theta\) has a velocity ratio of 10 : 1. The inclination of the plane to the horizontal is given by
A
tan\(\theta\) = \(\frac{1}{10}\)
B
cot\(\theta\) = \(\frac{1}{10}\)
C
cos\(\theta\) = \(\frac{1}{10}\)
D
sin\(\theta\) = \(\frac{1}{10}\)
8
A weightless vessel of dimensions 4m x 3m x 2m is filled with a liquid of density 1000kgm-3 and sealed. What is the maximum pressure this container can exert on a flat surface? [g = 10ms-2]
A
9 x 104NM-2
B
4 x 104NM-2
C
3 x 104NM-2
D
2 x 104NM-2
9
An object of mass 400g and density 600kgm-3 is suspended with a sting so that half of it is immersed in paraffin of density 900kgm-3. The tension in the string is
A
1.0N
B
3.0N
C
4.0N
D
5.0N
correct option: b
volume of object = \(\frac{400 \times 10^{-2}}{600}\)
= 0.00067m3
volume of paraffin displaced = \(\frac{1}{2}\) x 0.00067
= 0.00034m3
mass of paraffin = 900 x 34 x 10-5
= 0.3kg
weight of paraffin = 0.3 x 10
= 3N = upthrust = tension in the string
Users' Answers & Comments= 0.00067m3
volume of paraffin displaced = \(\frac{1}{2}\) x 0.00067
= 0.00034m3
mass of paraffin = 900 x 34 x 10-5
= 0.3kg
weight of paraffin = 0.3 x 10
= 3N = upthrust = tension in the string
10
The thermometric properties of the thermocouple is that is
A
e.m.f. changes with temperature
B
resistance changes with temperature
C
volume changes with temperature
D
pressure changes with resistance
correct option: a
Users' Answers & Comments