1991 - WAEC Physics Past Questions and Answers - page 2
11
The diagram above represents six maximum and minimum thermometer. If the temperature of the surrounding falls, which of the following correctly states how the thermometer would respond to the change in temperature?
A
S1, would move upward but S2 would not move
B
S1 would not move but S2 would move upwards
C
both S1 and S2 would move upwards
D
S1 would move downwards and S2 would move downwardw
correct option: b
Users' Answers & Comments12
A wire, 20m long is heated from a temperature of 5oC to 55oC. If the change in length is 0.020m, calculate the linear expansivity of the wire
A
1.0 x 10-3k-1
B
2.0 x 10-4k-1
C
2.0 x 10-5k-1
D
1.0 x 10-5k-1
correct option: c
\(\alpha = \frac{\Delta L}{L \Delta \theta} = \frac{0.020}{20 \times (55 - 5)} = 2.0 \times 10^{-5}\)
13
A water fall is 420m high. Calculate the difference in temperature of the water between the top and bottom of the water fall. Neglect heat loses(g = 10.0m-2 specific heat capacity of water = 4.20 x 10-3 JKg-1 K-1)
A
0.1oC
B
1.0oC
C
42oC
D
100oC
correct option: b
Potential Energy = Heat Energy
mgh = Mc\(\Delta \theta = \frac{gh}{c} = \frac{10 \times 240}{4.20 \times 10^3}\)
= 1.0oC
Users' Answers & Commentsmgh = Mc\(\Delta \theta = \frac{gh}{c} = \frac{10 \times 240}{4.20 \times 10^3}\)
= 1.0oC
14
The set-up illustrated above shows a capillary tube of uniform cross-sectional area in two different arrangements. Using the data in the diagrams. Calculate the pressure of the atmosphere
A
76cm of Hg
B
75cm of Hg
C
74cm of Hg
D
60cm of Hg
correct option: b
P1 = p + 15, p2 = p - 15
v1 = 30cm, v2 = 45cm
P1v1 = p2v2
p = 75cm of Hg
Users' Answers & Commentsv1 = 30cm, v2 = 45cm
P1v1 = p2v2
p = 75cm of Hg
15
A fixed mass of gas of volume 600cm3 at a temperature of 27oC is cooled at constant pressure to a temperature of 0oC. What is the change in volume?
A
54cm2
B
273cm2
C
300cm2
D
546cm2
correct option: a
\(\frac{V_1}{T_1} = \frac{V_2}{T_2}\)
T2 = 0 + 273 = 273k
V1 = 600
T1 = 27 + 273 = 300k
V2 = \(\frac{V_1T_2}{T_1}\) = 546cm
V1 - V2 = 54cm
Users' Answers & CommentsT2 = 0 + 273 = 273k
V1 = 600
T1 = 27 + 273 = 300k
V2 = \(\frac{V_1T_2}{T_1}\) = 546cm
V1 - V2 = 54cm
16
The boiling point of a liquid depends on the following except the
A
nature of the liquid
B
external pressure
C
volume of the liquid
D
impurities present in the liquid
correct option: c
Users' Answers & Comments17
A team trap is a component of the apparatus used in determining the specific latent heat of vaporisation of steam. In the steady steady state, the steam trap
A
stores the steam for future use
B
prevents the steam from escaping
C
ensures that only dry steam gets into the calorimeter
D
allows condensed steam to go into the calorimeter
correct option: c
Users' Answers & Comments18
a tap supplies water at 26oC while another supplies water at 82oC. If a man wishes to bathe with water at 40oC the ratio of hot mass of hot water to that of cold water required is
A
1:3
B
3:1
C
3:7
D
7:3
correct option: a
heat supplied by hot water = heat gained by cold water M1C(82 - 40) = M2C(40 - 26)
\(\frac{M_2}{M_1}\)= \(\frac{14}{42}\)
= 1: 3
Users' Answers & Comments\(\frac{M_2}{M_1}\)= \(\frac{14}{42}\)
= 1: 3
19
Melting ice cools an orange drink far better than the same mass of ice-cold water because
A
melting ice is lower temperature than ice-cold water
B
water has a higher specific heat than ice
C
ice floats and cools the air above the drink
D
ice absorbs latent heat during melting
correct option: d
Users' Answers & Comments20
The saturation vapour of a liquid depends on its
A
volume
B
temperature
C
mass
D
density
correct option: b
Users' Answers & Comments