1) Luminous objects a) Sun b) Books c) Chair d) Plants e) Toys f) Desk 2) Aritifical sources of light a) Sun b) Moon c) Stars d) Torch e) Firefly f) Don't know 3) Non lumnious object a) Sun b) Toys c) Tubelight d) Bulb e) Candle 4) Natural sources of light a) Torch b) Led light c) Candle d) Electric bulb e) Tubelights f) Fire-fly 5) Light is not form of energy a) True b) False 6) Light always travel in a straight line a) False b) True 7) Speed of light is 3×108 m/s a) False b) True

排行榜

视觉风格

选项

切换模板

恢复自动保存: