1. 勒克司是什麼的單位？(A)照度 (B)光束 (C)光度 (D)輝度

2. As shown in Fig.2, one block of mass M=2.00 kg is 1.00 m above the top of a massless spring. The force constant of the spring is k=200 N/m. This block is released from rest onto a spring, which is then compressed vertically. What is the maximum compression length of the spring? ($g=9.8 m/s^{2}$) (A) 0.55 m (B) 0.45 m (C) 0.36 m (D) 0.10 m (E) None