Frage 1
Frage
Which of the following is not generally observed in a geomagnetic storm?
Antworten
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Charged particles streaming out from the Sun
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Fluctuations in the Earth’s magnetic field
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Disruption of electrical power transmission
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Disruption of microwave propagation
Frage 2
Frage
A device that reverses magnetic field polarity to keep a dc motor rotating is
Antworten
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A solenoid
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An armature coil
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A commutator
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A field coil
Frage 3
Frage
When the speed at which a conductor is moved through a magnetic field is increased, the induced voltage
Antworten
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Increases
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Decreases
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Remains constant
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Reaches zero
Frage 4
Frage
For a given wirewound core, an increase in current through the coil
Antworten
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Reverses the flux lines
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Decreases the flux density
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Increases the flux density
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Causes no change in flux density
Frage 5
Frage
Which statements are correct?
Antworten
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Charges of opposite sign attract one another and charges of the same sign repel one another. Total charge in an isolated system is conserved. Charge is quantized.
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Charges of opposite sign repel one another and charges of the same sign attract one another. Total charge in an isolated system is conserved. Charge is quantized.
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Charges of opposite sign attract one another and charges of the same sign repel one another. Total charge in an isolated system is not conserved. Charge is quantized.
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Charges of opposite sign repel one another and charges of the same sign attract one another. Total charge in an isolated system is ot conserved. Charge is not quantized.
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No correct answer
Frage 6
Frage
When a box rests on the floor, it is acted upon by the gravitational and the _________________ force.
Antworten
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Centrifugal
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Acceleration
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Normal
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Inertia
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Friction
Frage 7
Frage
Motion is produced by
Antworten
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All forces
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Unbalanced forces
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Balanced forces
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The absence of force
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None of them
Frage 8
Frage
In inelastic collision between the two bodies __________.
Antworten
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Only momentum of the system is conserved
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Only the kinetic Energy of the system is conserved
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Both the kinetic Energy and Momentum of the system remain the same
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Total energy is not conserved
Frage 9
Frage
In elastic collision between the two bodies __________.
Antworten
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Only momentum of the system is conserved
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Only the kinetic Energy of the system is conserved
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Both the kinetic Energy and Momentum of the system remain the same
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Total energy is not conserved
Frage 10
Frage
When the force and displacement are parallel to each other, then work is __________.
Frage 11
Frage
In rotational motion, the quantity, which plays the same role as the inertial mass in linear motion, is called ___________.
Antworten
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Inertia
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Angular momentum
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Moment of inertia
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Torque
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Center of mass
Frage 12
Frage
A sound wave can be characterized as
Antworten
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A transverse wave
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A longitudinal wave
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A transverse wave or a longitudinal wave, depending on the nature of its source
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One that carries no energy
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A wave that does not require a medium to be transmitted from one place to the other
Frage 13
Frage
A woman sits on a spinning stool with her arms folded. When she extends her arms, which of the following occurs
Antworten
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She increases her moment of inertia, thus increasing her angular speed
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She increases her moment of inertia, thus decreasing her angular speed.
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She decreases her moment of inertia, thus increasing her angular speed
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She decreases her moment of inertia, thus decreasing her angular speed
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Her angular speed remains constant by conservation of angular momentum
Frage 14
Frage
The ability of a material to remain magnetized after removal of the magnetizing force is known as
Antworten
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Permeability
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Reluctance
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Hysteresis
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Retentivity
Frage 15
Frage
The induced voltage across a stationary conductor in a stationary magnetic field is
Antworten
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Zero
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Reversed in polarity
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Increased
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Decreased
Frage 16
Frage
When a solenoid is activated, the force that moves the plunger is
Frage 17
Frage
If a loop in a basic dc generator suddenly begins rotating at a faster speed, the induced voltage
Antworten
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Remains unchanged
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Reverses polarity
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Increases
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Decreases
Frage 18
Frage
You charge parallel-plate capacitor. When you pull the plates apart to a larger separation and battery remains connected to the capacitor
Frage 19
Frage
Induction current opposes the reason causing it. It is the shortest formulation of
Antworten
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Einstein’s law
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Lentz law
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Biot-Savart law
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Faraday’s law
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Ampere’s law
Frage 20
Frage
Paramagnetism is closely associated with
Antworten
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The torque
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The force exerted by electron dipole moments on each other
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The tendency of electron dipole moments to align with an applied magnetic field
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The exchange force between electrons
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The tendency of electrons dipole moments to align opposite to an applied magnetic field
Frage 21
Frage
The thermal conductivity is the analog to:
Antworten
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Thermal expansion
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Resistivity
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Elasticity
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Diffusivity
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Viscosity
Frage 22
Frage
Resistance of metals in classical theory of electric conductivity is caused by
Antworten
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Collision of free electrons with dislocations or clasters
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Collision of free electrons with impurity atoms in internodes
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Collision of free electrons with each other
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Collision of free electrons with vacancy defects
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Collision of free electrons with ions of crystal structure
Frage 23
Frage
Electric theory of dispersion was evaluated by:
Antworten
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Lorentz
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Newton
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Einstein
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Minkovsky
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Maxwell
Frage 24
Frage
Loop is uniformly rotating with angular velocity ω in uniform magnetic field. Loop has N coils and area of the loop is S. Rotating axis lies on loop’s plane and perpendicular to induction. What is the maximal EMF appeared in the loop:
Antworten
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NBS/2
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NBS
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NBScos(wt)
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NBSw/2
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NBSw
Frage 25
Frage
An electrton traveling with speed v around a circle of radius r is equivalent to a current of:
Antworten
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evr/2
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ev/r
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2πer/v
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2πev/r
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ev/2πr
Frage 26
Frage
An electromagnetic field propagates in +x direction. The electric field at a point in space is momentarily oriented in –z
direction. The magnetic field at that point is momentarily oriented in
Antworten
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–y direction
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+y direction
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+z direction
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+x direction
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-x direction
Frage 27
Frage
In RLC circuit angular frequency of AC source rises. Inductive reactance
Frage 28
Frage
The rapid exponential decay in just a few cycles of the charge on the plates of capacitor in an RLC circuit might be due to:
Antworten
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A large capacitance
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A small capacitance
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A large resistance
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A small resistance
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A large inductance
Frage 29
Frage
Intrinsic semiconductors are
Antworten
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Materials doped by impurities
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Pure elemental materials without impurities
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Materials doped by donor impurity
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Materials doped by acceptor impurity
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Any materials
Frage 30
Frage
In a charge-free region of space, closed container is placed in an electric field. A requirement for the total electric flux through the surface of the container to be zero is that
Antworten
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The field must be uniform
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The container must be oriented in a certain way
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The container must be symmetric
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The requirement does not exist – the total electric flux is zero no matter what