2001 - WAEC Physics Past Questions and Answers - page 2
11
Which of the following statements about elastic collision is correct?
A
momentum is lost due to the sound produced
B
loss of momentim is equal to loss in kinetic energy
C
both kinetic energy and momentum are conserved
D
kinetic energy is lost while momentum is conserved
correct option: c
Users' Answers & Comments12
Electrical resistance is a property of an electrical energy to be converted into
A
mechanical energy
B
heat energy
C
magnetic energy
D
chemical energy
correct option: b
Users' Answers & Comments13
A simple machine with an efficiency of 75% lifts a load of 5000N when a force of 500N is applied to it. Calculate the velocity ratio of the machine
A
10.0
B
13.3
C
17.5
D
25.0
correct option: b
M.A = \(\frac{load}{effort} \frac{5000N}{500N} = 10\)
V.R = \(\frac{M.A \times 100}{V} = \frac{10 \times 100}{75} = 13.3\)
Users' Answers & CommentsV.R = \(\frac{M.A \times 100}{V} = \frac{10 \times 100}{75} = 13.3\)
14
A screw jack with a Tommy bar of length 12cm is used to raise a car through a vertical height of 25cm by turning the Tommy bar through 50 revolutions. Calculate the approximate velocity ratio of the jack [\(\pi = 3.142\)]
A
21
B
38
C
48
D
151
correct option: d
P = \(\frac{25}{50} = 0.5\)
V.R = \(\frac{2\pi D}{p} = \frac{2 \times 3.142 \times 12}{0.5}\)
= 151
Users' Answers & CommentsV.R = \(\frac{2\pi D}{p} = \frac{2 \times 3.142 \times 12}{0.5}\)
= 151
15
a beam PQ pivoted at P carries a load of 80N as shown above. Calculate the effort E, required to keep it horizontal. [neglect the weight of the beam]
A
32.0N
B
26.7N
C
16.0N
D
13.3N
16
A resistance thermometer has a resistance of 20\(\Omega\) at 0oC and 85\(\Omega\) at 100oC. If its resistance is 52\(\Omega\)in a medium, calculate the corresponding temperature
A
49.2oC
B
60.6oC
C
80.0oC
D
84.7oC
correct option: a
85\(\Omega\) ........100oC
52\(\Omega\) ........\(\theta\)oC
20\(\Omega\) ........0oC
\(\frac{52 - 20}{85 - 20} = \frac{\theta - 0}{100 - 0}\)
\(\theta = \frac{32 \times 100}{65} = 49.2^oC\)
Users' Answers & Comments52\(\Omega\) ........\(\theta\)oC
20\(\Omega\) ........0oC
\(\frac{52 - 20}{85 - 20} = \frac{\theta - 0}{100 - 0}\)
\(\theta = \frac{32 \times 100}{65} = 49.2^oC\)
17
A given mass of an ideal gas has a pressure of 500Nm-2 at -13oC. If its volume remains constant. Calculate its pressure at 247oC.
A
25Nm-2
B
50Nm-2
C
500Nm-2
D
1000Nm-2
correct option: d
\(P_2 = \frac{p_1 \times T_2}{T_1} = \frac{500 - 520}{65}\)
= 1000Nm-2
Users' Answers & Comments= 1000Nm-2
18
The volume of an ideal gas at a pressure of 77cmHg and temperature 60oC is 24cm3. If the temperature and pressure are increased to 98oC
and 81cmhg respectively, calculate the new volume of the gas
and 81cmhg respectively, calculate the new volume of the gas
A
411.5cm3
B
267.1cm3
C
254.2cm3
D
112.7cm3
correct option: c
V2 = \(\frac{P_1V_1T_2}{P_2T_1} = \frac{77 \times 240 \times 371}{81 \times 333}\)
= 254.2cm3
Users' Answers & Comments= 254.2cm3
19
The amount of heat given out or absorbed when a substance changes its state at a constant temperature is known as
A
latent heat
B
heat capacity
C
specific latent heat
D
specific heat capacity
correct option: a
Users' Answers & Comments20
Which of the following physical qualities affects the saturated vapour pressure of a liquid ?
A
temperature
B
volume
C
mass
D
density
correct option: a
Users' Answers & Comments