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Multiple Questions & Answers on
Electricity And Magnetism
PHY 104
1
...
To convert a galvanometer to an ammeter, which
of the following must introduced (connection is to
the galvanometer)
(a) High resistance, connected in series
(b) Low resistance, connected in parallel
(c) High resistance, connected in parallel
Explanation
A galvanometer is converted into an ammeter by
connecting a low resistance in parallel with
galvanometer
...

3
...

This AC motor takes alternating current as input
whereas the DC motors takes in direct current
...
A capacitor is charged through a potential
difference of 200V, when a 0
...
The amount of energy released by it, when it
is discharged is:
(a) 5J
(b) 25J
(c) 10J
Explanation
U=200V
Q=0
...
1)(200)
U= 10J
5
...
It will
only tell if the body is a charged body or the body
has no charge
...
Energy lossses in a tranfomer include the
following execpt
(a) Histeresis loss
(b) Eddy current loss
(c) Transformation loss
Explanation
Type of lossess in a transformer
1
...
Hysteresis loss
3
...
Stay loss (leakage flux)
5
...
_____ is the process of removing excess charges
on an object
(a) Grounding
(b) Depolirization
(c) All
Explanation
Grounding is just the process of removing the
excess charge on an object by means of transfer of
electrons between it and another object
8
...
They begin from positive charge and ends
on equal negative charge
2
...
They give direction of electric field at any
point
4
...
Also, Where the lines are
parallel and equally spaced, the field is
uniform
5
...
They cut equipotential surfaces such as a
conductors at right angles
7
...
To charge by friction, the two materials must have
_____
(a) Same electron affinity
(b) Different electronegativity
(c) Different electron affinity
Explanation
When charging by friction, the atom of different
materials are forced to come together
...

Hence, there will be transfer of electron form the
the lower electron affinity atoms to the higher one
10
...
5x2 + 3x, where V is in volts and x
is in meters
...
Charging by rubbing in insulator involves
(a) Difference in quantized electrons
(b) Difference in electron affinities
(c) Sameness in electrode potential
Explanation
How charging by rubbing works
When two insulator are rubbed together, the
electron clouds of both insulators (from their
electrons) are brought close enough for them to
interact
...

Hence, the atoms of material with greater affinity
for electrons (electron affinity) will gain electrons
from the other material which is of lower electron
affinity
The material with greater affinity will be
negatively charged while the other will be
positively charged due to less electrons than
protons
12
...
A moving rod 45cm slides to the right with a speed
of 2cm/s in a magnetic field of 8T
...
6V
(b) 7
...
6V
Explanation
Lenght of the rod,l = 45cm = 0
...
45 x 2
e = 7
...
Positive charge is didtributed uniformly
throughout a non-conducting sphere
...
Which of following statement is not true?
(a) When the current flows in a wire, the electrons
as a whole acquire a fast drift speed
(b) When current flows in a wire, the magnectic
force on the moving electron is transmitted to the
wire
(c) When a wire is placed in a magnetic field, it
experiences on force
Explanation
Is true because when current flows in a wire, the
electrons moves at high speed
...
Since
it has a magnetic field, it will certainly experience
a magnetic force
Is true because when current flows in a wire, the
electrons possess a magnetic field and an electric
field
...
e having both north and south pole, not
one of them)
16
...

Mathematically,
V∝I
V = IR
Hence, resistance is te proportunity constant for
voltage∕potential difference and current
...
Which of the following is not correct?
(a) The direction of magnetic field inside the
solenoid is determined by righr hand thumb rule
(b) Fleming's left hand rulee applies in dynamo
(c) Fleming's right hand rule determines the
direction of induced current within an electric
generator
Explanation
B is wrong
...

Dynamo can also be reffered to as electrical
generator and flaming's right hand rule is applied
within electric generator (Option A)
Hence, Fleming's right hand ia applied in dynamo
not Fleming's Left hand rule
...
The electric field _____
(a) is always perpendicular to an equipotential
surface
(b) is always tangent to an equipotential surface
(c) makes an angle to an equipotential surface that
depends on the amount of change
Explanation
All points on an equipotential surface have the
same potential (i
...

The elecctric force neither helps nor hinders the
motion of an electric charge alog an equipotential
surface
...
A magnetic field exerts a force on a charged
particle
(a) always
(b) if the particle is moving along the field lines
(c) if the particle is moving across the field lines
Explanation
When a charged particle moves along (in the same
direction) the field lines, no force is exerted by the
magnectic field
Magnetic field only exert a force on a charged
particle when it moves an angle from the field
lines (i
...
J

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