2001 - JAMB Physics Past Questions and Answers - page 3
21
The cost of running five 60 W lamps and four 100 W lamps for 20 hours if electrical energy cost #10.00 per kwh is
A
280.00
B
160.00
C
120.00
D
140.00
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22
In a Daniel cell, the depolarizer, positive and negative electrodes are respectively
A
copper sulphate, copper and zinc
B
manganese dioxide, carbon and zinc
C
sulphuric acid, lead oxide and lead
D
potassium hydroxide, nickel and iron.
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23
when a piece of rectangular glass block is inserted between two parallel capacitor,at constant plate area and distance of separation, the capacitance of the capacitor will
A
increase
B
decrease
C
decrease then increase
D
remain constant
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24
the ratio of electrostatic force FE to gravitational force FG between two protons each of charge e and mass m, at a distance d is
A
e/4πԐoGm
B
e2/Gm2
C
Gm2/4πԐoe2
D
e2/4πԐoeGm2
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25
A cell can supply current of 0.4 A and 0.2 A through a 4.0Ω and 10.0Ω resistors respectively.
This internal resistance of the cell is
This internal resistance of the cell is
A
2.0Ω
B
1.0Ω
C
2.5Ω
D
1.5Ω
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26
The particles emitted when \( ^{39}_{19}K \text{ decay to } ^{39}_{19}K \) is
A
gamma
B
beta
C
electron
D
alpha
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27
I. Low pressure.
II. High pressure.
III. High p.d.
IV. Low p.d.
Which combination of the above is true of the conduction of electricity through gases?
II. High pressure.
III. High p.d.
IV. Low p.d.
Which combination of the above is true of the conduction of electricity through gases?
A
I and IV only
B
I and III only
C
II and IV only
D
II and III only
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28
The current through a resistor in an a.c circuit is given as 2 sin wt. Determine the d.c. equivalent of the current
A
A/√2
B
2/√A
C
2 A
D
√2 A
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29
The primary coil of a transformer has N turns and is connected to a 120 V a.c. power line. If the secondary coils has 1 000 turns and a terminal voltage of 1 200 volts, what is the value of N?
A
120
B
100
C
1 000
D
1 200
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30
Which of the following metals will provide the greatest shield against ionizing radiation
A
Iron
B
Manganese
C
Alminium
D
Lead
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