Shortcuts and Tricks for Solving Numerical Problems

1. Particle Motion:

• De Broglie Wavelength (λ): $$\lambda =\frac{h}{mv}$$ where h is Planck’s constant (6.626 x 10^-34 Js), m is the particle’s mass, and v is its velocity.

2. Photoelectric Effect:

• Maximum Kinetic Energy (KE_max): $$K{E}_{max}=hf-\phi$$ where h is Planck’s constant, f is the frequency of light, and φ is the work function of the metal surface.

3. Quantum Mechanics:

• Schrödinger Equation: $$-\frac{{\hslash }^2}{2m}\frac{d^2\psi (x)}{d{x}^2}+V(x)\psi (x)=E\psi (x)$$ where Ψ is the wave function, ħ is the reduced Planck constant, m is the particle’s mass, V is the potential energy function, E is the total energy, and x is the position.

4. Nuclear Reactions:

• Energy Released (Q): $$Q=(\mathrm{\Delta }m)c^2$$ where Δm is the mass defect (difference between the masses of reactants and products) and c is the speed of light.

5. Radioactive Decay:

• Half-Life (t1/2): $$t_{1/2}=\frac{ln(2)}{\lambda }$$ where λ is the decay constant.

6. X-Ray Scattering:

• Wavelength (λ): $$\lambda =2d\sin \theta$$ where d is the lattice spacing and θ is the scattering angle.

7. Diffraction:

• Angular Separation (θ): $$\theta ={\sin }^{-1}\left(\frac{m\lambda }{d}\right)$$ where m is the order of the bright spot, λ is the wavelength of light, and d is the grating spacing.

8. Relativistic Effects:

• Relativistic Mass (m_rel): $$m_{rel}=\frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}$$ where m_0 is the rest mass, v is the particle’s velocity, and c is the speed of light.

9. Atomic Energy Levels:

• Energy Difference (ΔE): $$\Delta E=hf$$ where h is Planck’s constant and f is the frequency of the light emitted or absorbed.

10. Quantum Harmonic Oscillator:

• Ground-State Energy (E_0): $$E_0=h{f}_0=\frac{1}{2}h\sqrt{\frac{k}{m}}$$ where f_0 is the ground-state frequency, h is Planck’s constant, k is the spring constant, and m is the effective mass.

Remember, these are just a few shortcuts and tricks, and in some cases, detailed calculations might be necessary.