w ciągu 12 h uległo rozpadowi 75% początkowych liczby jąder ile wynosi czas połowicznego zaniku. proszę o szybką pomoc!

[latex]Dane:\ t = 12 h\ m(t) = 0,25m_0\Szukane:\ T_{1/2} = ?\ m(t) = m_0* (frac{1}{2})^{ frac{t}{T_{1/2}}}\ frac{m(t)}{m_0} = (frac{1}{2})^{ frac{t}{T_{1/2}}}\ frac{0,25m_0}{m_0} = (frac{1}{2})^{ frac{12}{T_{1/2}}}\ frac{1}{4} = (frac{1}{2})^{ frac{12}{T_{1/2}}}\ (frac{1}{2})^2 = (frac{1}{2})^{ frac{12}{T_{1/2}}}\ \ 2 = { frac{12}{T_{1/2}}}\ 2T_{1/2} = 12\ T_{1/2} = 6 h [/latex]