M o d e r n P h y s i c s E x e r c i s e

Exercise

MCQs Multiple-choice questions covering key topics in modern physics.

Conceptual Questions Conceptual questions to enhance understanding of modern physics concepts.

Short Questions Short questions addressing specific ideas in modern physics.

Examples Worked examples to demonstrate problem-solving techniques in modern physics.

Numerical 1 A spaceship’s length is one-third of its proper length. Find its speed relative to the observer.

Numerical 2 A pendulum’s time period is 3 s in its inertial frame. Find its time period for an observer moving at $0.95c$.

Numerical 3 An electron moves at $0.75c$. Find its relativistic and classical momentum.

Numerical 4 An electron moves at $0.85c$. Find its total and kinetic energy in electron volts.

Numerical 5 Find the speed at which a proton’s mass triples.

Numerical 6 Find the speed at which a particle’s kinetic energy is 1.5 times its rest energy.

Numerical 7 Light of $3 \times 10^{-7} \, \mathrm{m}$ illuminates a metal with a 3.0 eV work function. Find $f_0$, $KE_{\text{max}}$, and $V_0$.

Numerical 8 Sun’s thermal radiation peaks in visible light. Estimate the sun’s temperature.

Numerical 9 A $50 \, \mathrm{keV}$ X-ray scatters at $90^\circ$. Find its energy after Compton scattering.

Numerical 10 Find the de Broglie wavelength of electrons accelerated through a $200 \, \mathrm{V}$ potential difference.

Numerical 11 Find the de Broglie wavelength of an electron accelerated through a $50 \, \mathrm{V}$ potential difference.

Numerical 12 An electron’s speed is $5 \times 10^3 \, \mathrm{m/s}$ with $0.003\%$ accuracy. Find the uncertainty in its position.

Numerical 13 An electron’s excited state lifetime is $10^{-8} \, \mathrm{s}$. Find its energy uncertainty.

Go to Modern Physics Notes Revisit theory section for a better understanding of the exercise.