wave motion part 1 (1 _ 40)
38:45
ch 1 lesson 1 part 2 (19 _ 37)
1:23:48
ch 2 lesson 3 (total internal reflection)
1:32:29
ch 1 lesson 3 part 1 (1 _ 30)
46:49
magnetic torque (Q60 to Q80)
1:08:01
ch 2 lesson 5(min. deviation & thin prism)
1:28:45
ch 2 lesson 1 (light properties)
24:38
Mechanic Repair A Hydraulic Jack And Broken Piston Of Tractor Trolly//Watch This Video
1:11:30