2014 - WAEC Physics Past Questions and Answers - page 2
11
The period of a simple pendulum X is 5s. What is the period of a simple pendulum Y which makes 50 vibrations in the same time it takes X to make 20 vibrations?
A
12.5s
B
2.5s
C
2.0s
D
1.2s
correct option: a
\(T_x = \frac{20}{5} = 4s\)
\(T_y = \frac{50}{4} = 12.5s\)
Users' Answers & Comments\(T_y = \frac{50}{4} = 12.5s\)
12
Alcohol of mass 21g and density 0.7g cm-3 is mixed with 10g of water. Determine the density of the mixture [density of water = 1.0gcm-3]
A
0.775gcm-3
B
0.875gcm-3
C
0.780gcm-3
D
0.880gcm-3
correct option: a
\(V_A = \frac{M}{D} = \frac{21}{0.7} = 30cm^3\)
\(V_w = \frac{M}{D} = \frac{10}{1} = 10cm^3\)
Vmixture = 30 + 10 = 40cm3
Mmixture = 21 + 10 = 31g
Dmixture = \(\frac{m}{v} = \frac{31}{40} = 0.775\)
Users' Answers & Comments\(V_w = \frac{M}{D} = \frac{10}{1} = 10cm^3\)
Vmixture = 30 + 10 = 40cm3
Mmixture = 21 + 10 = 31g
Dmixture = \(\frac{m}{v} = \frac{31}{40} = 0.775\)
13
A device that converts mechanical energy into electrical energy is
A
a dynamo
B
an electric motor
C
an induction coil
D
a transformer
correct option: a
Users' Answers & Comments15
A screw-jack has the distance between its successive threads as P and the length of its tommy bar as r. Its velocity ratio is given by the expression
A
\(\frac{2 \pi r^2}{P}\)
B
\(\frac{2 \pi r}{P}\)
C
\(\frac{2 \pi}{rp}\)
D
\(\frac{P}{2 \pi r}\)
correct option: b
Users' Answers & Comments16
Heat transfer by conduction is similar to wave motion because
A
there is increase in temperature
B
transfer of naterials is involved
C
xharged particles vibrates at right angles
D
no transfer of materials is involved
correct option: d
Users' Answers & Comments17
The temperature at which the water vapour in the air saturates the air and begins to condense is known as
A
dew point
B
critical point
C
boiling point
D
tripple point
correct option: a
Users' Answers & Comments18
The change of state from solid to liquid occurs
A
at constant temperature
B
when temperature is lower than the boiling point
C
when temperature is just near freezing point
D
when teemperature is equal ro the boiling point
correct option: a
Users' Answers & Comments19
which of the following types of thermometers can be used to measure a range of temperature from -50oC to 50o? i. Clinical ii. Mercury iii. Alcohol-in-glass
A
i only
B
ii only
C
iii only
D
i and ii only
correct option: c
Users' Answers & Comments20
A body of mass M kg rests on a plane inclined at an angle \(\theta\) to the horizontal. The component of the weight of the body parallel to the plane is
A
Mg sin \(\theta\)
B
Mg cos \(\theta\)
C
Mg tan \(\theta\)
D
Mg sec \(\theta\)
correct option: a
Users' Answers & Comments