2013 - JAMB Physics Past Questions and Answers - page 4
31
If the linear magnification of the objective and eyepiece convex lenses of a compound microscope are 4 and 7 respectively. Calculate the angular magnification of the microscope
A
2
B
3
C
11
D
28
32
The angle of deviation of light of various colours passing through a triangular prism increases in the order
A
red → green → blue
B
green → violet → blue
C
blue → red → green
D
blue → green → red
correct option: a
Users' Answers & Comments33
Calculate the force acting on an electron of charge 1.5 x 10-19C placed in an electric field of intensity 105Vm-1
A
1.5x10-11N
B
1.5x10-12N
C
1.5x10-13N
D
1.5x10-14N
34
Capacitors are used in the induction coil to
A
control circuits
B
prevent distortion of electric fields
C
prevent electric sparks
D
dissipate energy
correct option: c
Users' Answers & Comments35
A cell of emf 1.5V is connected in series with a 1Ω resistor and a current of 0.3A flows through the resistor. Find the internal resistance of the cell
A
4.0Ω
B
3.0Ω
C
1.5Ω
D
1.0Ω
correct option: a
r = \(\frac{E}{I} - R\)
r = \(\frac{1.5}{0.3} - 1\)
r = 4\(\Omega\)
Users' Answers & Commentsr = \(\frac{1.5}{0.3} - 1\)
r = 4\(\Omega\)
36
Which of the following obeys ohms laws?
A
electroytes
B
metals
C
diode
D
glass
correct option: b
Users' Answers & Comments37
A house has ten 40W and five 100W bulbs. How much will it cost the owner of the house to keep them lit for 10 hours if the cost of a unit is 5N?
A
N90
B
N50
C
N45
D
N5
correct option: c
P = 40 x 10 + 100 x 5
P = 400 + 500 = 900W
Cost = \(\frac{900 \times 10 \times 5}{1000}\)
Cost = N45
Users' Answers & CommentsP = 400 + 500 = 900W
Cost = \(\frac{900 \times 10 \times 5}{1000}\)
Cost = N45
38
An electric device is rated 2000W, 250V. Calculate the maximum current it can take
A
9A
B
8A
C
7A
D
6A
39
When a charge moves through an electric circuit in the direction of an electric force, it
A
gains both potential and kinetic energy
B
gains potential energy and lose kinetic energy
C
loses potential energy and gains kinetic energy
D
loses both potential and kinetic energy
correct option: a
Users' Answers & Comments40
To convert a galvanometer to a voltmeter, a
A
high resistance is connected to it in series
B
high resistance is connected to it in parallel
C
low resistance is connected to it in parallel
D
low resistance is connected to it in series
correct option: a
Users' Answers & Comments