1995 - WAEC Physics Past Questions and Answers - page 2
11
A mercury-in-glass thermometer reads - 20o at the ice point and 100o at the steam point. Calculate the celcius temperature corresponding to 70o on the thermometer.
A
41.0oC
B
50.0oC
C
62.5oC
D
70.0oC
correct option: e
Users' Answers & Comments12
A brass rod is 2 m long at a certain temperature. Calculate the linear expansion of the rod for a temperature change of 100K. (Take the linear expansivity of brass as 1.8 x 10'5K").
A
0.3600 m
B
0.1800 m
C
0.0360 m
D
0.0036m
correct option: d
Users' Answers & Comments13
A body of specific heat capacity 450J kg-1 K-1 falls to the ground from rest through a vertical height of 20m. Assuming conservation of energy, calculate the change in temperature of the body on striking the ground level. (g = 10ms-2)
A
0oC
B
2/9oC
C
4/9oC
D
9/4oC
correct option: c
Users' Answers & Comments14
Hot water at a temperature of t is added to twice that amount of water at a temperature of 30°C. If the resulting temperature of the mixture is 50°C. Calculate t.
A
90oC
B
80oC
C
50oC
D
40oC
correct option: a
Final Temperature = \(\frac{m_1 T_1 + m_2 T_2}{m_1 + m_2}\)
where m\(_1\) and m\(_2\) are the weights of the water in the first and second containers.
T\(_1\) and T\(_2\) are the temperatures of the water in the first and second container.
Given Final temperature = 50°C;
Let m\(_1\) = b, then m\(_2\) = 2b.
T\(_1\) = t; T\(_2\) = 30°C
\(\therefore 50 = \frac{b(t) + 2b(30)}{b + 2b}\)
\(50 = \frac{bt + 2b(30)}{3b}\)
\(50(3b) = bt + 2b(30) \implies 150b = b(t + 60)\)
\(150 = t + 60 \implies t = 150 - 60 = 90°C\)
15
An air bubble of volume 2 cm* is formed 20 m under water. What will be its volume when it rises to just below the surface of the water if the atmospheric pressure is equivalent to a height of 10 m of water?
A
6cm3
B
4cm3
C
3cm3
D
2cm3
correct option: b
Users' Answers & Comments16
The pressure of a given mass of gas changes from 200 Nm2 to 100 N m2, while its temperature drops from 127oC to - 73oC. Calculate the radio of the final volume of the gas to its initial volume.
A
2.4:1
B
2.0:1
C
1.2:1
D
1.0:1
correct option: d
Users' Answers & Comments17
The temperature of glass vessel containing 100cm3 of mercury is raised from 10oC to 100oC. Calculate the apparent cubic expansion of the mercury. (Real cubic expansivity of mercury = 1.82 x 10-4K-1) (Cubic expansivity of glass = 2.4 x 10-5K-1)
A
0.52cm3
B
1.42cm3
C
1.87cm3
D
5.22cm3
correct option: b
Users' Answers & Comments18
An iron rod of mass 2kg and at a temperature of 280oC is dropped into some quantity of water initially at a temperature of 30oC. lf the temperature of the mixture is 70oC, calculate the mass of the water. (Neglect heat losses to the surroundings). Specific heat capacity of iron = 460 J kgK) (Specific heat capacity of water = 4200 Jkg K)
A
0.58kg
B
0.77kg
C
1.15kg
D
1.50kg
correct option: c
Users' Answers & Comments19
How much heat is required to convert 20 g of ice at 0oC to water at the same temperature? (Specific latent heat of ice = 336 J g-1)
A
1.35 x 103J
B
5.38 x 103J
C
6.72 x 103J
D
7.06 x 103J
correct option: c
Users' Answers & Comments20
When two objects P and Q are supplied with the same quantity of heat, the temperature change in P is observed to be twice that in Q. lf the masses of P and Q are the same, calculate the ratio of the specific heat capacities of Q to P.
A
4 : 1
B
2 : 1
C
1 : 1
D
1 : 2
correct option: d
Users' Answers & Comments