题型:判断题 (1)如图所示,实线是一列简谐横波在t1=0时的波形图,虚线为t2=0.5s时的波形图,已知0<t2-t1<T,t1=0时x=2m处的质点A正向y轴正方向振动.①质点A的振动周期为______s; ②波的传播方向是______;③波速大小为______m/s.(2)如图所示,一细光束以45°的入射角从空气射向长方体透明玻璃砖ABCD的上表面E点,折射光线恰好过C点,已知BC=30cm,BE=103cm,求①此玻璃砖的折射率;②光束在玻璃砖中传播的时间. 查看答案
题型:判断题 —We all had a lot of fun at the barbecue yesterday. Pity you weren't there.—I really should have gone with you but I________on some remaining problems.A.workedB.was workingC.would workD.would have worked 查看答案