1994 - JAMB Physics Past Questions and Answers - page 2
11
Which of these statements are TRUE of pressure in liquids? i. pressure acts equally in all direction. ii. pressure decreases with depth. iii. pressure at the same level of a liquid is the same. iv pressure is dependent on the cross-sectional area of the barometer tube
A
i, iii only
B
i, ii, iii only
C
i, iii, and iv only
D
i, ii, iii and iv
correct option: a
Users' Answers & Comments12
The mass of a specific gravity bottle is 15.2g when it is empty. it is 24.8g when filled with kerosene and 27.2g when filled with distilled water. Calculate the relative density of kerosene
A
1.25
B
1.10
C
0.90
D
0.80
correct option: d
Masses of kerosene = 24.8 - 15.2
= 9.6
mass of H2O = 27.2 - 15.2
= 12
R.d = \(\frac{9.6}{12}\) = 0.8
Users' Answers & Comments= 9.6
mass of H2O = 27.2 - 15.2
= 12
R.d = \(\frac{9.6}{12}\) = 0.8
13
If a solid X floats in liquids P of relative density 2.0 and in liquid Q of relative density 1.5, it can be inferred that the
A
weight of P displaced is greater than that of Q
B
weight of P displaced is less than that of Q
C
volume of P displaced is greater than that of Q
D
volume of P displaced is less than that of Q
correct option: a
R.d \(\alpha\) weight of liquid displaced
\(\frac{\text {R.d of P}}{\text {R.d of Q}}\) = \(\frac{\text{weight of p displaced}}{\text{weight of Q displaced}}\)
\(\frac{2}{1.5}\) = \(\frac{\text {weight of p displaced}}{\text {weight of Q displaced}}\)
Users' Answers & Comments\(\frac{\text {R.d of P}}{\text {R.d of Q}}\) = \(\frac{\text{weight of p displaced}}{\text{weight of Q displaced}}\)
\(\frac{2}{1.5}\) = \(\frac{\text {weight of p displaced}}{\text {weight of Q displaced}}\)
14
The melting point of naphthalene is 78oC. What is this temperature in kelvin
A
100k
B
351k
C
378k
D
444k
15
A Motor Tyre is inflated to pressure of 2.0 x 105Nm-2 when the temperature of air is 27oC. What will be the pressure in it at 87oC assuming that the volume of the Tyre does not change?
A
2.6 x 105Nm-2
B
2.4 x 105Nm-2
C
2.2 x 105Nm-2
D
1.3 x 105Nm-2
correct option: b
\(\frac{p_1}{T_1}\) = \(\frac{p_2}{T_2}\)
\(\frac{2 \times 10^5}{27 + 273}\) = \(\frac{p_2}{87 + 273}\)
P2 = 2.4 x 105Nm-2
Users' Answers & Comments\(\frac{2 \times 10^5}{27 + 273}\) = \(\frac{p_2}{87 + 273}\)
P2 = 2.4 x 105Nm-2
16
When 100g of liquids L1 at 78oC was mixed with Xg of liquid L2 at 50oC, the final temperature was 60oC. Given that the specific heat capacity of L2is half that of L1, find x
A
50g
B
100g
C
150g
D
200g
correct option: c
Heat lost by L1 = heat gained by L2
cL1 = 2cL2
100 x 2cL2 x (78 - 60)
= xg x cL2 x (60 - 50)
xg = 150g
Users' Answers & CommentscL1 = 2cL2
100 x 2cL2 x (78 - 60)
= xg x cL2 x (60 - 50)
xg = 150g
17
Heat is supplied to a test tube containing 100g of ice at its melting point. The ice melts completely in 1 min.What is the power rating of the source of heat? [Latent heat of fusion of ice = 336Jg-1]
A
336W
B
450W
C
560W
D
600W
18
If a room is saturated with water vapour, the temperature of the room must be
A
at 0oC
B
above the dew point
C
at 100oC
D
below or at the dew point
correct option: d
Users' Answers & Comments19
Two similar kettles containing equal masses of boiling water are placed on a table. If the surface of one is highly polished and the surface of the other is covered with soot, Which of the following observations is correct
A
The two kettles will cool down at the same rate
B
the polished kettle cools down more quickly by conduction
C
the kettle covered with soot cools down more quickly because it is a good radiator
D
the kettle covered with soot cools down more quickly by the process of heat convection
correct option: c
Users' Answers & Comments20
The equation of transverse wave traveling along a string is given by Y = 0.3 sin(0.5x - 50t) where Y and X are in cm and t is in seconds.Find the maximum displacement of the particles from the equilibrium position
A
50.0cm
B
2.5 cm
C
0.5cm
D
0.3cm
correct option: d
Y = 0.3 sin(0.5x - 50t) compare with,
y = A sin(kx - wt)
A = 0.3m
Users' Answers & Commentsy = A sin(kx - wt)
A = 0.3m