Physics

# Key Equations

PhysicsKey Equations

## 22.1The Structure of the Atom

 energy of hydrogen electron in an orbital $E n =− 13.6eV n 2 (n=1,2,3,...) E n =− 13.6eV n 2 (n=1,2,3,...)$ energy of any hydrogen-like electron in orbital $E n = Z 2 n 2 E o ( n=1,2,3,... ) E n = Z 2 n 2 E o ( n=1,2,3,... )$ wavelength of light emitted by an electron changing states $1 λ =R( 1 n f 2 − 1 n i 2 ) 1 λ =R( 1 n f 2 − 1 n i 2 )$ wavelength of an orbital $n λ n =2π r n ( n=1,2,3,... ) n λ n =2π r n ( n=1,2,3,... )$ heisenberg’s uncertainty principle $ΔxΔp≥ h 4π ΔxΔp≥ h 4π$

 alpha decay equation $X Z A N → Y Z−2 A−4 N + H 2 4 e X Z A N → Y Z−2 A−4 N + H 2 4 e$ beta decay equation $X Z A N → Y Z+1 A N−1 +e+v X Z A N → Y Z+1 A N−1 +e+v$ gamma decay equation $X Z A N → X N +γ X Z A N → X N +γ$

## 22.3Half Life and Radiometric Dating

 radioactive half-life $N= N O e −λt N= N O e −λt$

## 22.4Nuclear Fission and Fusion

 energy–mass conversion $E=m c 2 E=m c 2$ proton-proton chain

 roentgen equivalent man $rem=rad×RBE rem=rad×RBE$