2015 - WAEC Physics Past Questions and Answers - page 5
41
A battery of emf 24V is connected to three resistor P, Q and R as illustrated in the given diagram. Determine the voltage across the resistor Q.
A
5V
B
10V
C
14V
D
24V
42
The mass of the earth is 6.0 x 1024kg and that of the moon is 7.0 x 1022kg. If the distance between them is 4.0 x 108m, calculate the force of attraction between them. [G = 6.7 x 10-11Nm2kg-2]
A
1.8 x 105N
B
1.8 x 1010N
C
1.8 x 1015N
D
1.8 x 1020N
correct option: d
F = \(\frac{GM_1M_2}{12^2}\)
F = 6.7 x 10-11x
F = \(\frac{M_1M_2}{R^2}\)
F = \(\frac{6.7 \times 10^{-11} \times 6.0 \times 10^{24} \times 7.0 \times 10^{22}}{(4 \times 10^8)^2}\)
= 1.8 x 1020N
Users' Answers & CommentsF = 6.7 x 10-11x
F = \(\frac{M_1M_2}{R^2}\)
F = \(\frac{6.7 \times 10^{-11} \times 6.0 \times 10^{24} \times 7.0 \times 10^{22}}{(4 \times 10^8)^2}\)
= 1.8 x 1020N
43
The angle which the direction of the earth magnetic field makes with the horizontal at a palace is know as.
A
angle of contact
B
angle of dip
C
angle of declination
D
magnetic meridian
correct option: b
Users' Answers & Comments44
What must be connected between the points P and Q to establish a steady current through the incomplete circuit diagram given?
A
Fuse
B
ammeter
C
Cell
D
voltmeter
correct option: c
Users' Answers & Comments45
When current flows through a moving-coil galvanometer, the force exerted on the pointer depends on the: i. strength of the current. ii. magnetic field strength. iii. length of the coil. Which of the statement(s) above is/are correct?
A
i only
B
ii only
C
i and iii only
D
i, ii and iii
correct option: c
Users' Answers & Comments46
in a nuclear fission process, the mass defect was 1.2 x 10-5kg. Calculate the energy released. [speed of the light in vacuum = c = 3.0 x 108ms-1]
A
1.08 x 1011J
B
5.20 x 1011J
C
1.08 x 1012J
D
2.50 x 1013J
47
Which of the following statements about diode is correct?
A
reverse bias diodes have low resistance
B
forward bias diodes have high resistance
C
forward bias diodes produce high current
D
forward bias diodes function as a result of heat
correct option: b
Users' Answers & Comments48
Which of the following radiations constitutes a stream of electrons?
A
Ramma rays
B
X-rays
C
Cathode rays
D
Radio waves
correct option: c
Users' Answers & Comments49
\(^{226}_{88}Ra\) emits two alpha particles to produce polonium(po) nuclide. The correct formula for the nuclide?
A
\(^{224}_{86}po\)
B
\(^{222}_{86}po\)
C
\(^{222}_{84}po\)
D
\(^{218}_{84}po\)
correct option: d
Users' Answers & Comments50
Two angles of a pentagon are in the ratio 2:3. The others are 60o each. Calculate the smaller of the two angles
A
72o
B
100o
C
120o
D
144o
correct option: d
The diagram given simple illustrates that a pentagon contains three \(\Delta\)s.
Two angles which are in the ratio 2:3 will have actual values 2xo, 3xo respectively. Thus 2xo + 3xo + 3 x 60 = 3x sum of angles of \(\Delta\)a
i.e. 5xo + 180o = 3 x 180o
5xo + 180o = 540o
5xo = 540o - 180o
5xo = 360o
xo = \(\frac{360^o}{5}\)
= 72o
Hence, the smaller of the two angles is
2 x 72o = 144o
Users' Answers & CommentsTwo angles which are in the ratio 2:3 will have actual values 2xo, 3xo respectively. Thus 2xo + 3xo + 3 x 60 = 3x sum of angles of \(\Delta\)a
i.e. 5xo + 180o = 3 x 180o
5xo + 180o = 540o
5xo = 540o - 180o
5xo = 360o
xo = \(\frac{360^o}{5}\)
= 72o
Hence, the smaller of the two angles is
2 x 72o = 144o