2013 - WAEC Physics Past Questions and Answers - page 2
11
From Newton's first law of motion,
A
a body can only undergo translational motion
B
once a body remains at rest no force acts on it
C
the net force acting in uniform linear motion is zero
D
a body's inertia is its weight
correct option: c
Users' Answers & Comments12
A body of mass 11kg is suspended from a ceiling fan by an aluminum wire of length 2m and diameter 2mm. Calculate the elastic energy stored in the wire [Young's modulus of aluminum is 7.0 x 1010Nm-2, g = 10ms-2, \(\pi\) = 3.142]`
A
1.1 x 10-1J
B
5.5 x 10-2J
C
1.1 x 10-4J
D
5.5 x 10-8J
correct option: b
e = \(\frac{4FI}{Y \pi d^2} = \frac{4 \times 11 \times 10 \times 2}{7 \times 10^3 \times 3.14(2 \times 10^{-2})^2}\)
= 0.001m
E = \(\frac{1}{2} Fe = \frac{1}{2} \times 110 \times 0.001\)
= 5.5 x 10-2J
Users' Answers & Comments= 0.001m
E = \(\frac{1}{2} Fe = \frac{1}{2} \times 110 \times 0.001\)
= 5.5 x 10-2J
13
The velocity ratio of an inclined plane
A
increases with increase in the angle of inclination
B
increases with decrease in the angle of inclination
C
decreases with decrease in the angle of inclination
D
is independent of the angle of inclination
correct option: a
Users' Answers & Comments14
Which of the following types of thermometer is used for the calibration of other thermometers?
A
liqud-in-glass thermometer
B
constant volume gas thermometer
C
optical pyrometer
D
thermocouple
correct option: b
Users' Answers & Comments15
The magnitude of the expansion or contraction of a substance depends on the i. temperature change ii. nature of the substance iii. size of the substance. Which of the statements above are correct?
A
i and ii only
B
ii and iii only
C
i and iii only
D
i, ii and iii
correct option: a
Users' Answers & Comments16
Highly polished silvery surfaces are
A
poor absorbers and poor emitters of radiation
B
poor absorbers and good emitters of radiation
C
good absorbers and poor emitters of radiation
D
good absorbers and good emitters of radiation
correct option: b
Users' Answers & Comments17
The volume of a given mass of gas at 27oC and 800 mmHg is 76cm2. Calculate its volume at s.t.p
A
100.0 cm3
B
72.8 cm3
C
60.0 cm3
D
36.4 cm3
correct option: b
\(V_2 = \frac{P_1V_1T_2}{P_2T_1} = \frac{800 \times 76 \times 273}{760 \times 300}\)
= 72.8cm3
Users' Answers & Comments= 72.8cm3
18
Ice of mass 10g at 5°C was completely converted to water at 0oC, calculate the quantity of heat used. [specific heat capacity of ice = 2.1 Jg\(^{-1}\)K\(^{-1}\), specific latent heat of fusion of ice = 336 Jg\(^{-1}\)]
A
105J
B
3255J
C
3465J
D
16821J
19
An electric heater has a resistance of 50\(\Omega\). When it is immersed in water and connected to mains source, it draws a current of 4.0A. Calculate the heat gained by the water if the heater is switched on for 2 minutes, assuming no heat losses to the surroundings
A
400J
B
1600J
C
24000J
D
96000J
20
When salt is dissolved in water, the freezing point of the water
A
increases
B
decreases
C
remains the same
D
increases and later decrease
correct option: b
Users' Answers & Comments