Q.1
Voltage can be induced in a wire by
  • a. moving the wire near a magnet.
  • b. moving a magnet near the wire.
  • c. changing the current in a nearby wire.
  • d. all of these
Q.2
Current sensitivity of a galvanometer can be increased by decreasing :
  • Magnetic field B
  • number of turns N
  • torsional constant K
  • Area A
Q.3
___ Law says that the Induced current is proportional to the change of magnetic flux
  • Lenz'
  • Faraday's
  • Ampere's
Q.4
A magnet is moved in and out of a coil of wire connected to a high-resistance voltmeter. If the number of coils doubles, the induced voltage
  • quadruples
  • doubles
  • is the same
  • halves
Q.5
The ratio of voltage sensitivity ( V_sVs​ ) and current sensitivity ( IsI_sIs​ ) of a moving coil galvanometer is (G =conductance)
  • 1G\frac{1}{G}G1​
  • 1G2\frac{1}{G^2}G21​
  • GGG
  • G2G^2G2
Q.6
Electromagnetic induction is change in ___________________.
  • surface area
  • magnetic poles
  • magnetic flux
Q.7
What benefit is gained by the addition of the iron core in an electromagnet?
  • It makes a strong magnet weaker
  • It makes a weak magnet stronger
  • There is no benefit at all
  • It lets currents interact with each other
Q.8
What is one way to increase the current in a wire?
  • Decrease the number of coils
  • Increase the number of coils
  • Move the magnet slower
  • Take the wire off of the magnet
Q.9
Which description best applies to Lenz's Law?
  • An induced current occurs when a magnet passes through a tube.
  • When a change in magnetic field occurs to a coil the direction of current goes in the in the other direction to this change.
  • The direction of an induced current is such to align with the change that created it.
  • A magnet is a tube is always slowed by its magnetic field.
Q.10
A magnet can move in a coil of wire to produce electricity in which system?
  • Generator
  • Motor
  • Magnet
  • Transformer
Q.11
What would happen if I move a bar magnet in and out of a coil of copper wire?
  • Electric current would disappear
  • The magnet would explode
  • Electric current will flow through the wire
  • It would produce a gravitational field
Q.12
A linear conductor carrying current if placed parallel to the direction of magnetic field, then it experiences ---------------- force.
  • Maximum
  • Zero
  • normal
  • None of these
Q.13
A wire in the form of a circular loop, of one turn carrying a current, produces magnetic induction B at the centre. If the same wire is looped into a coil of two turns and carries the same current, the new value of magnetic induction at the centre is
  • B
  • 2B
  • 4B
  • 8B
Q.14
To convert a moving coil galvanometer into on ammeter of given range, we must connect:
  • A suitable low resistance in series
  • A suitable low resistance in parallel
  • A suitable high resistance in parallel
  • A suitable high resistance in series
Q.15
Two wires of same length are shaped into a square and a circle if they carry same current, ratio of magnetic moment is :
  • 2 : pi
  • pi: 2
  • pi: 4
  • 4:pi
Q.16
An electric current passes through a long straight copper wire. At a distance 5 cm from the straight wire, the magnetic field is B. The magnetic field atcm from the straight wire would be
  • B/6
  • B/4
  • B/3
  • B/2
Q.17
Currents ofA and 2 A are flowing in opposite directions through two parallel wires A and B respectively. If the wire A is infinitely long and wire B is 2 m long, then force on wire B which is situated atcm from A, is
  • 8 x 10 ^ -5 N
  • 6 x 10 ^-5 N
  • 4 x 10 ^ -5 N
  • 2 X 10 ^ -5 N
Q.18
A deuteron of kinetic energykeV is describing a circular orbits of radius 0.5 m in a plane perpendicular to the magnetic field B. The kinetic energy of the proton that describes a circular orbit of same radius and inside same B is
  • 25 keV
  • 50 keV
  • 200 keV
  • 100 keV
Q.19
In a certain region of space, electric field E and magnetic field B are perpendicular to each other. An electron enters perpendicularly to both the fields and moves undeflected. The velocity of electron is
  • E/B
  • B/E
  • E x B
  • E.B
Q.20
What type of device can increase and decrease voltage?
  • Generators
  • Transformers
  • Galvanometers
  • Electric motors
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