A thin convex lens of focal length \( 5 \, \text{cm} \) and a thin concave lens of focal length \( 4 \, \text{cm} \) are combined together (without any gap) and this combination has magnification \( m_1 \) when an object is placed \( 10 \, \text{cm} \) before the convex lens. Keeping the positions of convex lens and object undisturbed a gap of \( 1 \, \text{cm} \) is introduced between the lenses by moving the concave lens away, which lead to a change in magnification of total lens system to \( m_2 \). The value of \( \left| \dfrac{m_1}{m_2} \right| \) is ________.
