Quick Quiz
Questions ▼
MCQs on Modern Physics. We covered all the MCQs on Modern Physics pdf in this post for free so that you can practice well for the exam.
Install our MCQTUBE Android app from the Google Play Store and prepare for any competitive government exams for free.
These types of competitive MCQs appear in exams like SSC CGL, CHSL, JE, MTS, Stenographer, CPO, Railway Group-D, NTPC, ALP, JE, RPF, Tech, Bank, Delhi Police Constable, UP Lekhpal, DSSSB, DDA ASO, BPSC Teaching, Defence, UPSSSC, UPSC (Pre), UPP, SI, UPTET, UPPCS, BPSC, BSSC, SBI, IBPS, LIC, State PCS, CDS, NDA, Assistant Commandant, and other Competitive Examinations, etc.
We created all the competitive exam MCQs into several small posts on our website for your convenience.
You will get their respective links in the related posts section provided below.
Related Posts:
MCQ on Modern Physics for Students
Which type of impurity atoms are used to dope pure silicon to create a p-type semiconductor?
(a) Phosphorus
(b) Boron
(c) Antimony
(d) Aluminum
Option b – Boron
What methods can be used to enhance the conductivity of pure germanium?
(a) Raising the temperature
(b) Adding acceptor-type dopants
(c) Adding donor-type dopants
(d) All of the above
Option d – All of the above
Doping a semiconductor with a donor element will result in
(a) an increase in hole concentration
(b) a decrease in hole concentration
(c) an increase in electron concentration
(d) a decrease in electron concentration
Option b – a decrease in hole concentration
As per Bohr’s atomic model for hydrogen
(a) the electron’s linear velocity is quantized
(b) the electron’s angular velocity is quantized
(c) the linear momentum of the electron is quantized
(d) the angular momentum of the electron is quantized
Option d – the angular momentum of the electron is quantized
Current conduction in semiconductors occurs due to
(a) electrons only
(b) holes only
(c) both electrons and holes
(d) neither electrons nor holes
Option c – both electrons and holes
At absolute zero temperature, a semiconductor
(a) has no free electrons
(b) lacks free electrons at all temperatures
(c) gains more free electrons with increasing temperature
(d) has fewer free electrons compared to conductors
Option a – has no free electrons
A p-type semiconductor is generally
(a) positively charged
(b) negatively charged
(c) electrically neutral
(d) neutral at 0 K but charged at higher temperatures
Option a – positively charged
Forward biasing in a p-n junction refers to the applied voltage
(a) increasing the junction potential barrier
(b) reducing the potential barrier
(c) equaling 1.5 volts
(d) none of the above
Option b – reducing the potential barrier
When a p-n junction is reverse biased, its V-I graph shows
(a) a leakage current
(b) a rise in the potential barrier
(c) no current flow
(d) a high current flow
Option a – a leakage current
The main purpose of using a Zener diode is for
(a) signal amplification
(b) current rectification
(c) voltage regulation
(d) all of the above
Option c – voltage regulation
The minimum amount of energy needed to release an electron from a metal surface is called
(a) atomic energy
(b) mechanical energy
(c) electric energy
(d) work function
Option d – work function
X-rays can be described as
(a) a flow of electrons
(b) a beam of positively charged particles
(c) electromagnetic waves of high frequency
(d) a stream of neutral particles
Option c – electromagnetic waves of high frequency
In p-type semiconductors, the dominant charge carriers are
(a) free electrons
(b) conduction electrons
(c) ions
(d) holes
Option d – holes
The energy required to ionize a hydrogen atom in its ground state is
(a) 13.6 MeV
(b) 13.6 eV
(c) 13.6 joules
(d) zero
Option b – 13.6 eV
Which planet is commonly known as the red planet?
(a) Mars
(b) Jupiter
(c) Saturn
(d) Uranus
Option a – Mars
In a p-n junction, the drift current flows
(a) from the n-region to the p-region
(b) from the p-region to the n-region
(c) from n to p in forward bias and p to n in reverse bias
(d) from p to n in forward bias and n to p in reverse bias
Option a – from the n-region to the p-region
The diffusion current across a p-n junction exceeds the drift current when
(a) the junction is forward biased
(b) the junction is reverse biased
(c) the junction has no external bias
(d) never, diffusion current is always smaller
Option a – the junction is forward biased
In a p-type semiconductor, the energy level of the acceptor atoms is
(a) close to the crystal’s valence band
(b) close to the conduction band
(c) just below the conduction band
(d) above the conduction band
Option a – close to the crystal’s valence band
In an n-type semiconductor, donor energy levels are positioned
(a) above the conduction band
(b) near the valence band
(c) close to the conduction band
(d) below the valence band
Option c – close to the conduction band
At room temperature, a semiconductor has
(a) an empty conduction band
(b) partially filled valence and conduction bands
(c) a fully filled valence band and partially filled conduction band
(d) a completely filled valence band
Option c – a fully filled valence band and partially filled conduction band
The diffusion current in a p-n junction flows
(a) from the n-side to the p-side
(b) from the p-side to the n-side
(c) from n to p when forward biased and reverse otherwise
(d) from p to n when forward biased and reverse otherwise
Option b – from the p-side to the n-side
What happens if a p-n junction’s terminals are connected using a wire?
(a) No continuous current will flow
(b) A steady current flows from n to p
(c) A steady current flows from p to n
(d) It depends on the wire’s resistance
Option a – No continuous current will flow
At absolute zero, the resistivity of an intrinsic semiconductor is
(a) zero
(b) infinite
(c) same as a conductor at room temperature
(d) equal to that of an insulator at room temperature
Option b – infinite
A photon is defined as
(a) a quantum of light
(b) a quantum of matter
(c) a positively charged particle
(d) a device to measure light intensity
Option a – a quantum of light
Which one of the following does not describe a photon’s property?
(a) rest mass
(b) momentum
(c) energy
(d) frequency
Option a – rest mass
A photon’s energy decreases if
(a) its amplitude increases
(b) its frequency increases
(c) its wavelength increases
(d) its wavelength decreases
Option c – its wavelength increases
What energy transformation takes place in a photoelectric cell?
(a) Light energy to heat energy
(b) Light energy to sound energy
(c) Light energy to electrical energy
(d) Electrical energy to light energy
Option c – Light energy to electrical energy
When the intensity of light of a fixed frequency falls on a metal surface, what happens to the photoelectric current?
(a) It reduces
(b) It increases
(c) It remains unchanged
(d) It fluctuates randomly
Option b – It increases
The principle behind the photoelectric effect relies on the conservation of
(a) Momentum
(b) Energy
(c) Angular momentum
(d) Mass
Option b – Energy
What occurs as the intensity of incident light becomes stronger?
(a) Photoelectric current rises
(b) Kinetic energy of electrons increases
(c) Photoelectric current decreases
(d) Kinetic energy of electrons decreases
Option a – Photoelectric current rises
The velocity of photoelectrons emitted from a metal surface
(a) is always zero
(b) is constant for all electrons
(c) can be infinitely large
(d) ranges from zero to a specific maximum value
Option d – ranges from zero to a specific maximum value
Which of the following processes does not emit electrons?
(a) Thermionic emission
(b) Emission of X-rays
(c) Photoelectric emission
(d) Secondary emission
Option b – Emission of X-rays
In Rutherford’s atomic model, electrons are described as
(a) Fixed in place
(b) Continuously in motion
(c) Located at the center
(d) Not specified
Option b – Continuously in motion
According to classical physics, the path of an electron in Rutherford’s atom would be
(a) Spiral
(b) Circular
(c) Parabolic
(d) Straight line
Option a – Spiral
The force that keeps electrons bound to the atomic nucleus is
(a) Electrostatic force
(b) Nuclear force
(c) Van der Waals force
(d) Gravitational force
Option a – Electrostatic force
Which phenomenon supports the particle behavior of light?
(a) Refraction
(b) Interference
(c) Polarization
(d) Photoelectric effect
Option d – Photoelectric effect
A key proof for the particle nature of cathode rays is
(a) Their ability to cause fluorescence
(b) Their movement through a vacuum
(c) Their deflection by electric and magnetic fields
(d) Their ability to form shadows
Option c – Their deflection by electric and magnetic fields
Electrons and photons having identical wavelengths will have the same
(a) Energy
(b) Speed
(c) Momentum
(d) Angular momentum
Option c – Momentum
Which element is best suited for photoelectric emission?
(a) Potassium
(b) Sodium
(c) Cesium
(d) Lithium
Option c – Cesium
Which effect supports the concept that matter exhibits wave-like behavior?
(a) Momentum of electrons
(b) Diffraction of electrons
(c) Momentum of photons
(d) Diffraction of photons
Option b – Diffraction of electrons
G.P. Thomson demonstrated the wave nature of matter using which phenomenon?
(a) Diffraction
(b) Refraction
(c) Polarization
(d) Scattering
Option b – Refraction
In the Davisson-Germer experiment, the beam reflected from a crystal contains
(a) Photons
(b) Protons
(c) X-rays
(d) Electrons
Option d – Electrons
The charge-to-mass ratio (specific charge) for cathode rays is
(a) Always the same
(b) Always different
(c) Dependent on the cathode material
(d) Dependent on the gas in the tube
Option a – Always the same
When cathode rays are exposed to a magnetic field at right angles to their direction, they are
(a) Accelerated
(b) Deflected towards the magnetic north
(c) Deflected towards the magnetic south
(d) Bent upward out of the paper’s plane
Option d – Bent upward out of the paper’s plane
As light travels from a rarer to a denser medium, what change does its speed undergo?
(a) Speed increases
(b) Speed increases going from dense to rare
(c) Speed decreases
(d) Speed remains unaffected by the medium
Option c – Speed decreases
An object is located at the center of curvature of a concave mirror with a 16 cm focal length. If moved 8 cm closer to the focus, what will be the nature of the image formed?
(a) Real and magnified
(b) Virtual and magnified
(c) Real and diminished
(d) Virtual and diminished
Option a – Real and magnified
What is the definition of magnification?
(a) Actual size of object ÷ Observed size
(b) Observed size of object ÷ Actual size
(c) Actual size minus observed size
(d) Observed size of object ÷ Actual size
Option b – Observed size of object ÷ Actual size
What is the term for the bending of light as it travels from one medium to another?
(a) Refraction
(b) Diffraction
(c) Propagation
(d) None of the above
Option a – Refraction
When a light ray moves from a denser medium into a rarer medium, it bends
(a) toward the normal and slows down
(b) away from the normal and speeds up
(c) away from the normal and slows down
(d) toward the normal and speeds up
Option b – away from the normal and speeds up
When light enters a glass slab, what changes?
(a) Only its frequency
(b) Both frequency and speed
(c) Frequency stays constant
(d) Frequency and wavelength vary
Option c – Frequency stays constant
Specific gravity refers to the ratio of
(a) Density of a substance to density of water
(b) Density of a substance to water’s density at 0°C
(c) Water’s density at 4°C to that of the substance
(d) Density of a substance to water’s density at 4°C
Option d – Density of a substance to water’s density at 4°C
Why might a diver suffer ear pain underwater?
(a) Due to oxygen deficiency
(b) Due to atmospheric pressure
(c) Because of water pressure
(d) All the above reasons
Option c – Because of water pressure
Which instrument measures atmospheric pressure?
(a) Ammeter
(b) Barometer
(c) Potentiometer
(d) Lactometer
Option b – Barometer
At which temperature is water’s density exactly 1 g/cc?
(a) 0°C
(b) 4°C
(c) 25°C
(d) 100°C
Option b – 4°C
When is the density of water at its highest? ( MCQs on Modern Physics )
(a) 0°C
(b) Minimum at 0°C
(c) Maximum at 4°C
(d) Minimum at -4°C
Option c – Maximum at 4°C
A line spectrum results when excited vapors at low pressure exist in which state? ( MCQs on Modern Physics )
(a) Atomic state
(b) Molecular state
(c) Nuclear state
(d) None of the above
Option a – Atomic state
Which statements correctly describe Bohr’s model of the hydrogen atom?
(I) Electron speed decreases in higher orbits
(II) Orbit radius is related to the principal quantum number
(III) Orbital frequency is inversely related to the cube of the quantum number
(IV) Binding force increases in outer orbits
(a) I and II
(b) II and IV
(c) I, II, and III
(d) II, III, and IV
Option a – I and II
Which hydrogen spectral series falls in the visible range? ( MCQs on Modern Physics )
(a) Paschen series
(b) Balmer series
(c) Lyman series
(d) Brackett series
Option b – Balmer series
Emission of electrons under light exposure is known as
(a) Thermionic emission
(b) Photoelectric emission
(c) High-field emission
(d) Auto-electronic emission
Option b – Photoelectric emission
If the voltage across an X-ray tube is doubled and other factors remain constant, how does the cutoff wavelength change? ( MCQs on Modern Physics )
(a) No change
(b) Becomes twice as long
(c) Is reduced to half
(d) Becomes four times longer
Option c – Is reduced to half
As the principal quantum number increases, what happens to a hydrogen atom’s potential energy? ( MCQs on Modern Physics )
(a) It decreases
(b) It increases
(c) No change
(d) Doesn’t increase
Option b – It increases
What determines the wavelength of characteristic X-rays? ( MCQs on Modern Physics )
(a) Temperature of the target
(b) Size of the target
(c) Atomic number of the target
(d) Mass of the target
Option c – Atomic number of the target
Why are continuous X-rays called white X-rays?
(a) They behave like white light
(b) They are produced in abundance
(c) Their spectrum covers a continuous range
(d) They affect photographic plates like light
Option c – Their spectrum covers a continuous range
When a hydrogen atom transitions to an excited state ( MCQs on Modern Physics )
(a) Potential energy rises, kinetic energy falls
(b) Potential energy drops, kinetic energy rises
(c) Both energies increase
(d) Both kinetic and potential energies decrease
Option a – Potential energy rises, kinetic energy falls
As the value of quantum number increases, how does energy gap between levels change? ( MCQs on Modern Physics )
(a) Remains constant
(b) Increases
(c) Decreases
(d) Varies unpredictably
Option c – Decreases
Which theory best explains the photoelectric effect? ( MCQs on Modern Physics )
(a) Wave theory
(b) Electromagnetic theory
(c) Quantum theory
(d) None of these
Option c – Quantum theory
The maximum kinetic energy of photoelectrons varies with ( MCQs on Modern Physics )
(a) Intensity of light
(b) Frequency of light
(c) Speed of light
(d) Changes randomly
Option b – Frequency of light
If a photosensitive metal isn’t emitting electrons, what must be increased to trigger emission? ( MCQs on Modern Physics )
(a) Intensity
(b) Frequency
(c) Wavelength
(d) None of these
Option b – Frequency
What is true about the work function in photoelectric effect?
(a) It varies by material
(b) It’s same for all metals
(c) It depends on light intensity
(d) It depends on frequency
Option a – It varies by material
In the photoelectric effect, electrons are released ( MCQs on Modern Physics )
(a) Proportional to radiation amplitude
(b) With velocity linked to light frequency
(c) Irrespective of the emitter material
(d) Only if light frequency exceeds a certain threshold
Option d – Only if light frequency exceeds a certain threshold
We covered all the MCQs on modern physics above in this post for free so that you can practice well for the exam.
Check out the latest MCQ content by visiting our mcqtube website homepage.
Also, check out:
