NEET UG Modern Physics — practice questions
48 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice NEET UG Modern Physics in the app →A metal is illuminated with light of frequency less than its threshold frequency. Which outcome is correct?The series of hydrogen lines lying entirely in the ultraviolet region is the:The hydrogen series lying in the visible region is the:The Rydberg formula for hydrogen lines is 1/λ = R(1/n₁² − 1/n₂²) where for the Balmer series n₁ equals:The Rydberg constant R for hydrogen is approximately:For hydrogen-like ions of atomic number Z, the energy of the n-th level is:The orbital speed of the electron in the n-th Bohr orbit is proportional to:The total energy of an electron in a Bohr orbit equals:De Broglie supported Bohr's quantisation by suggesting that the electron orbit must contain an integer number The angular momentum L of the electron in the n-th Bohr orbit is:In the visible-region Balmer series, the longest-wavelength line corresponds to the transition:In Bohr's model, an electron in a stationary orbit:Bohr's model could explain the hydrogen spectrum but failed to:The wavelength of a photon emitted when an electron in hydrogen jumps from n = 3 to n = 2 is approximately:Number of spectral lines emitted when a hydrogen atom de-excites from n = 4 to n = 1 (all possible cascades) iThe energy required to excite a hydrogen atom from the ground state to its first excited state (n = 1 to n = 2In Bohr's model, the centripetal force on the electron is supplied by the:The de Broglie wavelength of an electron in the n = 1 Bohr orbit of hydrogen equals the:For the ground state of singly ionised helium (He⁺, Z = 2), the energy of the electron is:The difference between the incident energy and threshold energy for an electron in a photoelectric effect expeA waveform shown when applied to the following circuit will produce which of the following output waveform. AsThe figure shows the variation of photocurrent with anode potential for a photo-sensitive surface for three diA radioactive sample consists of two distinct species having equal number of atoms initially. The mean life tiThe following diagram indicates the energy levels of a certain atom when the system moves from $4E$ level to $The de-Broglie wavelength associated with a particle of mass $10^{-6}$ kg with a velocity of $10 \, ms^{-1}$ iPer NCERT §4.5 (definition of momentum), the momentum p of a body of mass m moving with velocity v is which?Per NCERT §4.5, the SI unit of force is the newton, with one newton equal to which value?Per NCERT §4.5, the impulse-momentum theorem states that the impulse on a body equals which quantity?Atoms of an element differing in mass are called:How many isotopes does hydrogen have?Which element is said to have 32 isotopes?The nuclei of isotopes of one element contain the same number of:The density of a nucleus is:Nuclei are compared to a drop of:The difference between a nucleus and its constituents in mass is the:The mass defect is explained by whose equivalence of mass and energy?The average energy needed to remove one nucleon is the binding energy:The binding energy curve is flat between mass numbers:In that flat region the binding energy per nucleon is about:Who discovered radioactivity, in 1896?Becquerel made his discovery while studying:Becquerel's emission penetrated black paper and:Radioactivity is a decay undergone by a nucleus that is:How many types of radioactive decay occur in nature?In alpha decay, which nucleus is emitted?In beta decay, which particles may be emitted?A positron has the same mass as an electron but a charge that is:In gamma decay, what is emitted?