Chọn B. Vì :
Ta có : \(Q_n= m_n.c_n.(t-t_1)\)
\(Q_d=m_d.c_d.(t-t_1)\) Nên \(\dfrac{Q_n}{Q_d}\) = \(\dfrac{c_n}{c_d}\) = 2
Vậy \(Q_n = 2Q_d\)
Copyright © 2021 HOCTAP247