Quiz
PhysX #2
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Perguntas do quiz (30)
1Which of the following is not generally observed in a geomagnetic storm?
- ACharged particles streaming out from the Sun
- BFluctuations in the Earth’s magnetic field
- CDisruption of electrical power transmission
- DDisruption of microwave propagation
2A device that reverses magnetic field polarity to keep a dc motor rotating is
- AA solenoid
- BAn armature coil
- CA commutator
- DA field coil
3When the speed at which a conductor is moved through a magnetic field is increased, the induced voltage
- AIncreases
- BDecreases
- CRemains constant
- DReaches zero
4For a given wirewound core, an increase in current through the coil
- AReverses the flux lines
- BDecreases the flux density
- CIncreases the flux density
- DCauses no change in flux density
5Which statements are correct?
- ACharges 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.
- BCharges 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.
- CCharges 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.
- DCharges 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.
- ENo correct answer
6When a box rests on the floor, it is acted upon by the gravitational and the _________________ force.
- ACentrifugal
- BAcceleration
- CNormal
- DInertia
- EFriction
7Motion is produced by
- AAll forces
- BUnbalanced forces
- CBalanced forces
- DThe absence of force
- ENone of them
8In inelastic collision between the two bodies __________.
- AOnly momentum of the system is conserved
- BOnly the kinetic Energy of the system is conserved
- CBoth the kinetic Energy and Momentum of the system remain the same
- DTotal energy is not conserved
9In elastic collision between the two bodies __________.
- AOnly momentum of the system is conserved
- BOnly the kinetic Energy of the system is conserved
- CBoth the kinetic Energy and Momentum of the system remain the same
- DTotal energy is not conserved
10When the force and displacement are parallel to each other, then work is __________.
- AMinimum
- BMaximum
- CNone of these
- DDepends on force magnitude
11In rotational motion, the quantity, which plays the same role as the inertial mass in linear motion, is called ___________.
- AInertia
- BAngular momentum
- CMoment of inertia
- DTorque
- ECenter of mass
12A sound wave can be characterized as
- AA transverse wave
- BA longitudinal wave
- CA transverse wave or a longitudinal wave, depending on the nature of its source
- DOne that carries no energy
- EA wave that does not require a medium to be transmitted from one place to the other
13A woman sits on a spinning stool with her arms folded. When she extends her arms, which of the following occurs
- AShe increases her moment of inertia, thus increasing her angular speed
- BShe increases her moment of inertia, thus decreasing her angular speed.
- CShe decreases her moment of inertia, thus increasing her angular speed
- DShe decreases her moment of inertia, thus decreasing her angular speed
- EHer angular speed remains constant by conservation of angular momentum
14The ability of a material to remain magnetized after removal of the magnetizing force is known as
- APermeability
- BReluctance
- CHysteresis
- DRetentivity
15The induced voltage across a stationary conductor in a stationary magnetic field is
- AZero
- BReversed in polarity
- CIncreased
- DDecreased
16When a solenoid is activated, the force that moves the plunger is
- AAn electromagnetic field
- BA permanent magnetic field
- CVarying voltage
- DA steady current
17If a loop in a basic dc generator suddenly begins rotating at a faster speed, the induced voltage
- ARemains unchanged
- BReverses polarity
- CIncreases
- DDecreases
18You charge parallel-plate capacitor. When you pull the plates apart to a larger separation and battery remains connected to the capacitor
- ADecreases
- BRemains the same
- CAlternates
- DIncreases
- EChanges in an unpredictable way
19Induction current opposes the reason causing it. It is the shortest formulation of
- AEinstein’s law
- BLentz law
- CBiot-Savart law
- DFaraday’s law
- EAmpere’s law
20Paramagnetism is closely associated with
- AThe torque
- BThe force exerted by electron dipole moments on each other
- CThe tendency of electron dipole moments to align with an applied magnetic field
- DThe exchange force between electrons
- EThe tendency of electrons dipole moments to align opposite to an applied magnetic field
21The thermal conductivity is the analog to:
- AThermal expansion
- BResistivity
- CElasticity
- DDiffusivity
- EViscosity
22Resistance of metals in classical theory of electric conductivity is caused by
- ACollision of free electrons with dislocations or clasters
- BCollision of free electrons with impurity atoms in internodes
- CCollision of free electrons with each other
- DCollision of free electrons with vacancy defects
- ECollision of free electrons with ions of crystal structure
23Electric theory of dispersion was evaluated by:
- ALorentz
- BNewton
- CEinstein
- DMinkovsky
- EMaxwell
24Loop 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:
- ANBS/2
- BNBS
- CNBScos(wt)
- DNBSw/2
- ENBSw
25An electrton traveling with speed v around a circle of radius r is equivalent to a current of:
- Aevr/2
- Bev/r
- C2πer/v
- D2πev/r
- Eev/2πr
26An 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- A–y direction
- B+y direction
- C+z direction
- D+x direction
- E-x direction
27In RLC circuit angular frequency of AC source rises. Inductive reactance
- ARemains the same
- BIncreases
- COscillates about certain value
- DAlternates
- EDecreases
28The rapid exponential decay in just a few cycles of the charge on the plates of capacitor in an RLC circuit might be due to:
- AA large capacitance
- BA small capacitance
- CA large resistance
- DA small resistance
- EA large inductance
29Intrinsic semiconductors are
- AMaterials doped by impurities
- BPure elemental materials without impurities
- CMaterials doped by donor impurity
- DMaterials doped by acceptor impurity
- EAny materials
30In 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
- AThe field must be uniform
- BThe container must be oriented in a certain way
- CThe container must be symmetric
- DThe requirement does not exist – the total electric flux is zero no matter what
Informações
- Descrição
- just quiz
- Autor
- Hanzo Conard
- Idioma
- English
- Visualizações
- 61
- Etiquetas
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