Physics 1 - Quiz for UPSC, SSC, Bank, Railways & Govt Exams

A car battery is rated at 80 A ? h. An ampere-hour is a unit of:

power

energy

current

charge

Correct Answer: 4

Current has units:

kilowatt?hour

coulomb/second

coulomb

volt

Correct Answer: 2

Current has units:

kilowatt?hour

ampere

coulomb

volt

Correct Answer: 2

The units of resistivity are:

ohm

ohm?meter

ohm/meter

ohm/meter2

Correct Answer: 2

The rate at which electrical energy is used may be measured in:

watt/second

watt?second

watt

joule?second

Correct Answer: 3

Energy may be measured in:

kilowatt

joule?second

watt

watt?second

Correct Answer: 4

Which one of the following quantities is correctly matched to its unit?

Power ? kW?h

Energy ? kW

Potential difference ? J/C

Current ? A/s

Correct Answer: 3

Current is a measure of:

force that moves a charge past a point

resistance to the movement of a charge past a point

energy used to move a charge past a point

amount of charge that moves past a point per unit time

Correct Answer: 4

A 60-watt light bulb carries a current of 5 A. The total charge passing through it in one hour is

120 C

3600 C

3000 C

1800 C

Correct Answer: 4

A 0-ohm resistor has a constant current. If 00 C of charge flow through it in 4 minutes what is the value of the current

3.0 A

5.0 A

11 A

15 A

Correct Answer: 4

Conduction electrons move to the right in a certain wire. This indicates that:

the current density and electric field both point right

the current density and electric field both point left

the current density points right and the electric field points left

the current density points left and the electric field points right

Correct Answer: 2

Two wires made of different materials have the same uniform current density. They carry the same current only if

their lengths are the same

their cross-sectional areas are the same

both their lengths and cross-sectional areas are the same

the potential differences across them are the same

Correct Answer: 2

In a conductor carrying a current we expect the electron drift speed to be:

much greater than the average electron speed

much less than the average electron speed

about the same as the average electron speed

less than the average electron speed at low temperature and greater than the average

Correct Answer: 2

Two substances are identical except that the electron mean free time for substance A is twice the electron drift speed in A is

the same as in B

twice that in B

half that in B

four times that in B

Correct Answer: 2

The current is zero in a conductor when no potential difference is applied because:

the electrons are not moving

the electrons are not moving fast enough

for every electron with a given velocity there is another with a velocity of equal magnitude

equal numbers of electrons and protons are moving together

Correct Answer: 3

The current density is the same in two wires. Wire A has twice the free-electron concentration

twice that of electrons in B

four times that of electrons in B

half that of electrons in B

one-fourth that of electrons in B

Correct Answer: 3

If nJ is the current density and d nA is a vector element of area then the integral $ nJ ? d nA over an area represents

the electric flux through the area

the average current density at the position of the area

the resistance of the area

the current through the area

Correct Answer: 4

If the potential difference across a resistor is doubled:

only the current is doubled

only the current is halved

only the resistance is doubled

only the resistance is halved

Correct Answer: 1

Of the following, the copper conductor that has the least resistance is:

thin, long and hot

thick, short and cool

thick, long and hot

thin, short and cool

Correct Answer: 2

A cylindrical copper rod has resistance R. It is reformed to twice its original length with no change of volume .its new resistance is

R

2R

4R

8R

Correct Answer: 3

The resistance of a rod does NOT depend on:

its temperature

its material

its length

the shape of its fixe cross-sectional area

Correct Answer: 4

A current of 5 A exists in a 60-ohm lamp. The applied potential difference is:

15 V

30 V

60 V

120 V

Correct Answer: 2

For an ohmic substance the resistivity is the proportionality constant for:

current and potential difference

current and electric field

current density and potential difference

current density and electric field

Correct Answer: 4

For an ohmic resistor, resistance is the proportionality constant for:

potential difference and electric field

current and electric field

current and length

E. current and potential difference

Correct Answer: 4

For an ohmic substance, the resistivity depends on:

the electric field

the potential difference

the current density

the electron mean free time

Correct Answer: 4

For a cylindrical resistor made of ohmic material, the resistance does NOT depend on:

the current

the length

the cross-sectional area

the resistivity

Correct Answer: 1

For an ohmic substance, the electron drift velocity is proportional to:

the cross-sectional area of the sample

the length of the sample

the mass of an electron

the electric field in the sample

Correct Answer: 4

You wish to triple the rate of energy dissipation in a heating device. To do this you could triple

the potential difference keeping the resistance the same

the current keeping the resistance the same

the resistance keeping the potential difference the same

the resistance keeping the current the same

Correct Answer: 4

The total number of electron states with n = and f = for an atom is:

two

four

six

eight

Correct Answer: 3

The possible values for the magnetic quantum number ms of an electron in an atom:

depend on n

depend on f

depend on both n and f

E. are ?1/2

Correct Answer: 4

The Stern-Gerlach experiment makes use of:

a strong uniform magnetic field

a strong non-uniform magnetic field

a strong uniform electric field

a strong non-uniform electric field

Correct Answer: 2

To observe the Zeeman effect one uses:

a strong uniform magnetic field

a strong non-uniform magnetic field

a strong uniform electric field

a strong non-uniform electric field

Correct Answer: 2

An electron in a K shell of an atom has the principal quantum number:

n = 0

n = 1

n = 2

n = 3

Correct Answer: 2

A photon with the smallest wavelength in the continuous z-ray spectrum is emitted when:

an electron is knocked from a K shell

a valence electron is knocked from the atom

the incident electron becomes bound to the atom

the incident electron loses all its energy in a single decelerating event

Correct Answer: 4

Characteristic K x-radiation of an element occurs when:

the incident electron is absorbed by a target nucleus

the incident electron is scattered by a target atom without an energy loss

an electron is ejected from an outer shell of a target atom

an electron in a target atom makes a transition to the lowest energy state

Correct Answer: 4

The Pauli exclusion principle is obeyed by:

all particles

all charged particles

all particles with spin quantum numbers of 1/2

all particles with spin quantum numbers of 1

Correct Answer: 3

Which of the following subshells cannot exist?

3p

2p

4d

2d

Correct Answer: 4

The group of atoms at the ends of periods of the periodic table are called:

alkali metals

rare earths

transition metal atoms

inert gas atoms

Correct Answer: 4

The group of atoms at the beginning of periods of the periodic table are called:

alkali metal atoms

rare earth atoms

transition metal atoms

alkaline atoms

Correct Answer: 1

A laser must be pumped to achieve:

a metastable state

fast response

stimulated emission

population inversion

Correct Answer: 4

Photons in a laser beam are produced by:

transitions from a metastable state

transitions to a metastable state

transitions from a state that decays rapidly

splitting of other photons

Correct Answer: 1

In a helium-neon laser, the laser light arises from a transition from a state to a state

He, He

Ne, Ne

He, Ne

Ne, He

Correct Answer: 2

he purpose of the mirrors at the ends of a helium-neon laser is:

to assure that no laser light leaks out

to increase the number of stimulated emissions

to absorb some of the photons

to keep the light used for pumping inside the laser

Correct Answer: 2

A laser beam can be sharply focused because it is:

highly coherent

plane polarized

intense

highly directional

Correct Answer: 4

The ?e? in laser stands for:

electric

emf

energy

emission

Correct Answer: 4

Possible units for the density of states function N (E) are:

J/m3

1/J

m?3

J?1?m?3

Correct Answer: 4

The density of states for a metal depends primarily on:

the temperature

the energy

the density of the metal

the volume of the sample

Correct Answer: 2

The Fermi-Dirac occupancy probability P (E) varies between:

0 and 1

0 and infinity

1 and infinity

?1 and 1

Correct Answer: 1

A hole refers to:

a proton

a positively charged electron

an electron that has somehow lost its charge

the absence of an electron in an otherwise filled band

Correct Answer: 4

For a pure semiconductor the Fermi level is:

in the conduction band

well above the conduction band

in the valence band

E. near the center of the gap between the valence and conduction bands

Correct Answer: 4

What is the effect on the capacitance of a parallel plate capacitor if the distance between the plates is halved while keeping the area constant?

halved

doubled

unchanged

zero

Correct Answer: 2

If the speed of light in a medium is ?, and the refractive index of the medium is ?, what is the speed of light in vacuum?

v/n

v-n

v+n

v.n

Correct Answer: 2

In quantum mechanics, what does the Heisenberg uncertainty principle state about position and momentum?

Both can be known precisely at the same time

The more precisely one is known, the less precisely the other can be known

Both are independent of each other

Their product is zero

Correct Answer: 2

What is the phenomenon where light waves spread out after passing through a narrow slit called?

Reflection

Refraction

Diffraction

Dispersion

Correct Answer: 3

In a Young�s modulus experiment, the stress applied to a wire is doubled while keeping the strain constant. What happens to the Young�s modulus?

Unchanged

Halves

Double

Zero

Correct Answer: 1

Physics 1 Quiz - UPSC, SSC, Bank, Railways & Govt Exams

A car battery is rated at 80 A ? h. An ampere-hour is a unit of:

Current has units:

Current has units:

The units of resistivity are:

The rate at which electrical energy is used may be measured in:

Energy may be measured in:

Which one of the following quantities is correctly matched to its unit?

Current is a measure of:

A 60-watt light bulb carries a current of 5 A. The total charge passing through it in one hour is

A 0-ohm resistor has a constant current. If 00 C of charge flow through it in 4 minutes what is the value of the current

Conduction electrons move to the right in a certain wire. This indicates that:

Two wires made of different materials have the same uniform current density. They carry the same current only if

In a conductor carrying a current we expect the electron drift speed to be:

Two substances are identical except that the electron mean free time for substance A is twice the electron drift speed in A is

The current is zero in a conductor when no potential difference is applied because:

The current density is the same in two wires. Wire A has twice the free-electron concentration

If nJ is the current density and d nA is a vector element of area then the integral $ nJ ? d nA over an area represents

If the potential difference across a resistor is doubled:

Of the following, the copper conductor that has the least resistance is:

A cylindrical copper rod has resistance R. It is reformed to twice its original length with no change of volume .its new resistance is

The resistance of a rod does NOT depend on:

A current of 5 A exists in a 60-ohm lamp. The applied potential difference is:

For an ohmic substance the resistivity is the proportionality constant for:

For an ohmic resistor, resistance is the proportionality constant for:

For an ohmic substance, the resistivity depends on:

For a cylindrical resistor made of ohmic material, the resistance does NOT depend on:

For an ohmic substance, the electron drift velocity is proportional to:

You wish to triple the rate of energy dissipation in a heating device. To do this you could triple

The total number of electron states with n = and f = for an atom is:

The possible values for the magnetic quantum number ms of an electron in an atom:

The Stern-Gerlach experiment makes use of:

To observe the Zeeman effect one uses:

An electron in a K shell of an atom has the principal quantum number:

A photon with the smallest wavelength in the continuous z-ray spectrum is emitted when:

Characteristic K x-radiation of an element occurs when:

The Pauli exclusion principle is obeyed by:

Which of the following subshells cannot exist?

The group of atoms at the ends of periods of the periodic table are called:

The group of atoms at the beginning of periods of the periodic table are called:

A laser must be pumped to achieve:

Photons in a laser beam are produced by:

In a helium-neon laser, the laser light arises from a transition from a state to a state

he purpose of the mirrors at the ends of a helium-neon laser is:

A laser beam can be sharply focused because it is:

The ?e? in laser stands for:

Possible units for the density of states function N (E) are:

The density of states for a metal depends primarily on:

The Fermi-Dirac occupancy probability P (E) varies between:

A hole refers to:

For a pure semiconductor the Fermi level is:

What is the effect on the capacitance of a parallel plate capacitor if the distance between the plates is halved while keeping the area constant?

If the speed of light in a medium is ?, and the refractive index of the medium is ?, what is the speed of light in vacuum?

In quantum mechanics, what does the Heisenberg uncertainty principle state about position and momentum?

What is the phenomenon where light waves spread out after passing through a narrow slit called?

In a Young�s modulus experiment, the stress applied to a wire is doubled while keeping the strain constant. What happens to the Young�s modulus?