final physics MCQ

A beam of light travels from air into water. Which one of the following statements is necessarily true?

Both speed and wavelength increase.

Both the wavelength and frequency increase.

The frequency decreases and the wavelength is unchanged.

The speed increases and wavelength is unchanged.

The frequency increases and the wavelength is unchanged.

Both speed and wavelength decrease.

Both speed and wavelength decrease

When an object is placed 20 cm from a lens, a real image is formed. Which one of the following conclusions is incorrect?

The lens is a converging lens.

The image may be reduced or enlarged.

The focal length of the lens is greater than 20 cm.

The image is inverted.

The image distance can be less than 20 cm.

The focal length of the lens is greater than 20 cm.

If the index of refraction for a given material is 1.33, what is the speed of light in the material relative to the speed of light in vacuum, c?

no material can have an index of refraction greater than 1 since light cannot travel faster than c

c

3c/4

4c/3

c/2

3c/4

When an object is placed 15 cm from a lens, a virtual image is formed. Which one of the following conclusions is incorrect?

The lens may be a convex or a concave lens.

If the lens is a converging lens, the focal length must be greater than 15 cm.

If the image is upright, the lens must be a diverging lens.

If the image is reduced, the lens must be a diverging lens.

None of the above statements is incorrect.

If the image is upright, the lens must be a diverging lens

The bending of light as it moves from one medium to another with differing indices of refraction is due to the change in what property of the light?

Wavelength

Time Period

Speed

Frequency

Amplitude

Speed

An object is placed at the focal point of a thin diverging lens of focal length, f . What is the image distance?

—f

At infinite distance

—2f

—f/2

—1/f

—f/2

Which one of the following statements concerning electromagnetic waves is false?

In vacuum, all electromagnetic waves travel at the same speed.

X-rays have longer wavelengths than radio waves.

Lower frequency electromagnetic waves can be produced by oscillating circuits.

They consist of mutually perpendicular electric and magnetic fields that oscillate perpendicular to the direction of the propagation.

Electromagnetic waves carry energy.

x-rays have longer wavelengths than radio waves

Linearly polarize light is incident on a polarizer. The angle between the transmission axis and the incident electric field is 44°. What percentage of the incident intensity is transmitted?

84%

52%

43%

38%

72%

52%

The amplitude of the electric field component of an electromagnetic wave is decreased from 3E to E. What is the corresponding change in the intensity of the wave?

The intensity increases by a factor of nine.

The intensity decreases by a factor of nine.

The intensity decreases by a factor of three.

The intensity increases by a factor of three.

The intensity is unchanged by the increase in E.

the intensity decreases by a factor of nine

Two polarizing sheets have their transmission axes parallel so that the intensity of unpolarized light transmitted through both of them is a maximum. Through what angle must either sheet be rotated if the transmitted intensity is 25% of the incident intensity?

22.6°

77.3°

43.1°

0°

54.7°

43.1°

laser uniformly illuminates an area with green light that has an average intensity of 550 W/m². What is the rms value of the electric field of this light?

643 N/C

405 N/C

455 N/C

891 N/C

322 N/C

455 N/C

An electromagnetic wave has an electric field with a peak value of 250 N/C. What is the average intensity of the wave?

120 W/m2

0.89 W/m2

170 W/m2

83 W/m2

0.66 W/m2

83 W/m²

Complete the following sentence: The various colors of visible light differ in

frequency only.

both frequency and their speed in vacuum.

wavelength only.

both frequency and wavelength.

their speeds in vacuum.

both frequency and wavelength

A radio wave sent from the surface of the earth reflects from the surface of the moon and returns to the earth. The elapsed time between the generation of the wave and the detection of the reflected wave is 4 s. Determine the distance from the surface of the earth to the surface of the moon.

6 × 10^8 m
3 × 10^8 m
4 × 10^8 m
10 × 10^8 m
12 × 10^8 m

6 × 10^8 m

Which of the following colors of visible light has the longest wavelength?

Green

Blue

Yellow

Red

Violet

red

Which one of the following statements concerning the wavelength of an electromagnetic wave in a vacuum is true?

The wavelength is independent of the speed of the wave for a fixed frequency.

The wavelength is inversely proportional to the speed of the wave.

The wavelength is same for all types of electromagnetic waves.

The wavelength is directly proportional to the frequency of the wave.

The wavelength is inversely proportional to the frequency of the wave.

the wavelength is inversely proportional to the frequency of the wave

Which one of the following waves is fundamentally different than the other four?

Visible light.

Gamma rays.

Sound waves.

Radio waves.

Ultra-Violet radiation.

sound waves

Which one of the following statements concerning electromagnetic waves is false?

The existence of electromagnetic waves was predicted by Maxwell.

X-rays have shorter wavelengths than radio waves.

The do not require a physical medium for propagation.

In vacuum, all electromagnetic waves have the same wavelength.

They consist of mutually perpendicular electric and magnetic fields.

in vacuum, all electromagnetic waves have the same wavelength

A long, straight wire is in the same plane as a conducting loop. The wire carries a decreasing current I in the direction shown in the figure. Which of the following statements is true?

There will be an induced emf and a clockwise current.

There will be no induced emf and no induced current.

There will be an induced emf and a counter-clockwise current.

There will be an induced emf but no current.

there will be an induced emf and a clockwise current

A circular loop of wire is lying flat on a horizontal table in an external magnetic field, and you are looking down at it. There is an induced counter-clockwise current in the loop. If the external field is directed upward toward you, then what is happening to the magnitude of this external field?

increasing

not enough information given

decreasing

not changing

decreasing

A circular coil of copper wire is lying flat on a horizontal table. A bar magnet is held with its south pole downward, vertically above the center of the coil. The magnet is released from the rest and falls toward the coil. As viewed from the above, as the magnet falls, it induces

a counter-clockwise current in the loop

an emf but no electric current in the loop

a clockwise current in the loop

no current in the loop

a clockwise current in the loop

A conducting loop of wire is placed in a magnetic field that is normal to the plane of the loop. Which one of the following actions will not result in an induced current in the loop?

Rotate the loop about an axis that is parallel to the field and passes through the center of the loop.

Increase the strength of the magnetic field.

decrease the area of the loop.

Rotate the loop about an axis that is perpendicular to the field and passes through the center of the loop.

decrease the strength of the magnetic field.

rotate the loop about an axis that is parallel to the field and passes through the center of the loop

A loop with a resistance is pushed to the left at a constant speed by a force F. At the instant shown in the figure, the loop is partially in and partially out of a uniform magnetic field. Induced current flows from left to right through the resistor. What is the direction of the original magnetic field in which the loop is being moved?

to the left.

into the paper.

toward the top of the page.

to the right.

out of the paper.

into the paper

A rectangular coil lies flat on a horizontal surface. A bar magnet is held above the center of the coil with its north pole pointing down. What is the direction of the induced current in the coil?

clockwise.

not enough information given.

no current is induced.

counter-clockwise.

no current is induced

An electron moving with a velocity v enters a region which contains both electric and magnetic fields. The electric field is pointing along the +z axis and magnetic field is pointing along the +y axis. The net force on the electron is zero and it moves in a straight line. What is the direction in which the electron is moving?

along +z axis

along +x axis

along −x axis

along −z axis

along −yaxis

along −x axis

A proton traveling due west in a region that contains only a magnetic field experiences a vertical upward force (away from the surface of the earth). What is the direction of the magnetic field?

south

east

west

north

down

north

Which one of the following statements concerning the magnetic force on a charged particle in a magnetic field is true?

The magnetic force is a maximum if the particle is stationary.

The magnetic force is zero if the particle moves perpendicular to the field.

The magnetic force acts in the direction of motion for a positively charged particle.

The magnetic force depends on the component of the particle's velocity that is perpendicular to the field.

The magnetic force is a maximum if the particle moves parallel to the field.

the magnetic force depends on the component of the particle’s velocity that is perpendicular to the field

A current carrying wire is placed in a uniform magnetic field. If the direction of the current flow is along −x axis and the direction of the magnetic field is along −y axis, what is the direction of the magnetic force experienced by the current wire?

along the −z axis

along the −y axis

along the +y axis

along the −x axis

along the +z axis

along the +z axis

A current-carrying, rectangular coil of wire is placed in a magnetic field. The magnitude of the torque on the coil is not dependent upon which one of the following quantities?

The length of the sides of the loop.

The area of the loop.

The orientation of the loop relative to the magnetic field.

The direction of the current in the loop.

The magnitude of the current in the loop.

The direction of the current in the loop.

A charged particle is moving in a uniform, constant magnetic field. Which one of the following statements concerning the magnetic force exerted on the particle is false?

The magnetic force does no work on the particle.

The magnetic force does not change the speed of the particle.

The magnetic force changes the velocity of the particle.

The magnetic force does not change the kinetic energy of the particle.

None of the above statements is true.

None of the above statements is true.

A simple series circuit contains a resistance R and ideal battery. If a second resistor is connected in parallel with R,

The total current from the battery in the circuit will increase.

The rate of energy dissipation in R will increase.

The voltage across R will decrease.

The equivalent resistance of the circuit will increase.

The current through R will decrease.

The total current from the battery in the circuit will increase.

Two wires, A and B, and a variable resistance R, are connected in series to a battery. Which one of the following results will occur if the resistance of R is decreased?

The voltage across A and B will increase.

The current through the entire circuit will increase.

The current through A and B will increase.

The current through the entire circuit will decrease.

The voltage across the entire circuit will increase.

The current through the entire circuit will increase.

Two parallel-plate capacitors with the same plate area but different capacitances are connected in parallel to a battery. Both capacitors are filled with air. The quantity that is the same for both capacitors when they are fully charged is:

plate separation

charge on the positive plate

potential difference (Voltage across the plates)

energy density

electric field between the plates

potential difference (Voltage across the plates

Two parallel plate capacitors with different plate separation but the same capacitance are connected in series to a battery. Both capacitors are filled with air. The quantity that is NOT the same for both the capacitors when they are fully charged is:

stored energy

charge on the positive plate

surface area of the plates

voltage across the capacitors

dielectric constant

surface area of the plates

Two identical capacitors, each with capacitance C, are connected in parallel and the combination is connected in series to a third identical capacitor. The equivalent capacitance of this arrangement is:

2C

C

3C

3C/2

2C/3

2C/3

Let Q denote the charge, V denote the potential difference (voltage) and U denote stored energy. Of these quantities, capacitors in series must have the same:

Q only

Q and U only

V and U only

V only

U only

Q only

Which one of the following statements concerning resistance is true?

The resistance of a semiconductor increases with increasing temperature.

The resistance is the same for all samples of the same material.

The resistance of a wire increases with the length of the wire.

The resistance of a conductor decreases with increasing temperature.

The resistance of a wire is increases with the thickness of the wire.

The resistance of a wire increases with the length of the wire.

The current through a certain heater wire is found to be fairly independent of its temperature. If the current through the heater wire is doubled, the amount of energy delivered by the heater in a given time interval will

decrease by a factor of four

increase by a factor of two

decrease by a factor of two

increase by a factor of four

increase by a factor of eight

increase by a factor of four

The potential difference across the ends of a wire is doubled in magnitude. If Ohm’s law is obeyed, which one of the following statements concerning the resistance of the wire is true?

The resistance decreases by a factor of four.

The resistance is not changed.

The resistance is one half of its original value.

The resistance increases by a factor of four.

The resistance is twice its original value

The resistance is not changed.

Which one of the following situations results in a conventional electric current that flows northward?

a beam of protons moves northward

a beam of protons moves eastward

an electric dipole moves southward

a beam of electrons moves southward

a beam of electrons moves northward

a beam of electrons moves southward

Which of the following statements define "electromotive force"?

the force that accelerates electrons through a wire when a battery is connected.

the maximum electric potential energy stored within a battery.

the maximum capacitance between the terminals of a battery.

the force that accelerates protons through a wire when a battery is connected.

the maximum potential difference between the terminals of the battery.

the maximum potential difference between the terminals of the battery

Which one of the following statements concerning resistors in series is true?

The current through each resistor is the same .

The rate at which charge flows through each resistor depends on its resistance.

The power dissipated by each resistor is the same.

The total current through the resistors is the sum of the current through each resistor.

The voltage across each resistor is the same.

the current though each resistor is the same

A region of space contains a uniform electric field, directed towards the right, as shown in the Figure below. Which statement about this situation is correct?

The potentials at point A and B are equal, and the potential at point C is higher than the potential at point A.

The potential at point A is the highest, the potential at point B is the second highest, and the potential at point C is the lowest.

The potential at all three locations, A, B, and C is the same.

The potentials at point A and B are equal, and the potential at point C is lower than the potential at point A.

The potential at point C is the highest, the potentials at A and B are equal and are lower than the potential at C.

The potentials at point A and B are equal, and the potential at point C is lower than the potential at point A.

The work done in moving a 2C charge between two points in the electric field is 10 J. What is the potential difference between those two points?

-10 V

5 V

-5 V

10 V

-5 V

At a distance r from an isolated negative charge

the electric potential is negative but the magnitude of the electric field is positive

both the electric potential and the magnitude of the electric field are positive

both the electric potential and the magnitude of the electric field are negative

the electric potential is positive but the magnitude of the electric field is negative

none of the above statements is true

the electric potential is negative but the magnitude of the electric field is positive

A negative charge in an external electric field, if free, tries to move

in the direction of the electric field

toward infinity

in the opposite direction of the electric field

from regions of higher potential to regions of lower potential

in the opposite direction of the electric field

As a proton moves in a direction of the electric field

its total energy increases

it is losing kinetic energy

its electric potential energy remains constant

it is losing electric potential energy

it is gaining electric potential energy

it is losing electric potential energy

The electric potential at a certain point in space is 10 V. What is the electric potential energy of a -3.0μC  charge placed at that point?

0 J

+30 J

-30 μJ

-30 J

+30 μJ

-30 μJ

Two identical small charged spheres are at a certain distance apart, and each one initially experiences an electrostatic force of magnitude F due to the other. With time, charge gradually diminishes on both spheres by leaking off. When one sphere loses half its initial charge and the other sphere loses one third of its initial charge, what will be magnitude of the electrostatic force on each one?

12F

(1/8)F

(1/3)F

(1/6)F

(1/12)F

(1/3)F

Which one of the following statements is true concerning the magnitude of the electric field at a point in space?

It is a measure of the total charge on the object.

It is a measure of the ratio of the charge on an object to its mass

It is a measure of the electric force per unit mass on a test charge.

It is a measure of the electric force per unit charge on a test charge.

It is a measure of the electric force on any charged object.

It is a measure of the electric force per unit charge on a test charge

The magnitude of the electric field at a distance of two meters from a positive charge is E. What is the magnitude of the electric field at the same location, if the magnitude of the charge is doubled?

4E

E

2E

E/4

E/2

2E

Two charged particles, A and B are located near each other. The magnitude of the force A exerts on B is independent of

the magnitude of charge on B

the magnitude of charge on A

the sign of charge on B

the distance between A and B.

the sign of charge on B

Complete the following statement: When a glass rod is rubbed with silk cloth, the rod becomes positively charged as

negative charges are transferred from the silk to the rod.

positive charges are created on the surface of the rod.

negative charges are transferred from the rod to the silk.

positive charges are transferred from the silk to the rod.

positive charges are transferred from the rod to the silk.

negative charges are transferred from the rod to the silk.

A particle traveling horizontally enters a region where a uniform electric field is directed upward. The particle experiences an upward force once it has entered the field. What is the charge on the particle?

No charge (neutral particle)

not enough information is given.

Positive charge

Negative charge

positive charge